Jeeze Louise, what did the coin docs do before PCGS started conserving? I expect there are plenty of em out there as good as if not better than the one/s at PCGS. WE don't know who bought the coin or who conserved it/had it conserved, but does it really matter? >>
I know who made it and the owner conserved it personally, but I'm not sure why it matters.
Jeeze Louise, what did the coin docs do before PCGS started conserving? I expect there are plenty of em out there as good as if not better than the one/s at PCGS. WE don't know who bought the coin or who conserved it/had it conserved, but does it really matter? >>
I know who made it and the owner conserved it personally, but I'm not sure why it matters. >>
I was gonna say that this is the much more likely scenario. Dealers dip coins all of the time and send them in successfully with little to NO cost.
A guy I met at a show, once, told me that he dips EVERYTHING before sending it in, even if it's stone white!! How twisted is that??!! I cringed at the thought of it!!
Sometimes, it’s better to be LUCKY than good. 🍀 🍺👍
Every time someone refers to dipping as conserving I get annoyed. Just call it what it is and quit trying to justify the practice through some false sense of preservation.
I can't believe there are actually people saying PCGS grading this higher than AU58 is the correct grade compared to the NGC grade. What did you guys slip in your koolaid today? It has quite obvious wear (even after the stripping) on the obverse hair and breasts, top of the eagles head, wings...?
Jeeze Louise, what did the coin docs do before PCGS started conserving? I expect there are plenty of em out there as good as if not better than the one/s at PCGS. WE don't know who bought the coin or who conserved it/had it conserved, but does it really matter? >>
I know who made it and the owner conserved it personally, but I'm not sure why it matters. >>
It doesn't really, but I think it's naive to believe that just because PCGS started advertising dipping coins, that the big crackout gurus and coin docs have just suddenly quit doing it. I suppose the telltale thing here is that had a coin doc done it, it would have been done within days of being sold at Heritage in 2012.
Any astute collector will ask themselves, 'where does a coin sit for 140 years and not tone? Dip a copper piece and see what happens, it's ruined. Dip a silver piece and..........well, you know it's not original.
Leo
The more qualities observed in a coin, the more desirable that coin becomes!
"Original" in numismatics is an ideal...hard to define and impossible to prove (at least with classic coins). While I'm a big proponent of "originality", I know that really the best I can do is look for indicators of an absence of originality. The coin in the OP epitomizes what I look for, and what I avoid.
<< <i>Frankly when a 145 YO coin comes in the door looking like it was just struck that morning, it shouldn't raise any eyebrows?
I highly doubt that the coin in question was cracked out of the holder, dipped and submitted to PCGS for grading, you're smarter than that!! more than likely it was submitted to PCGS in the NGC holder for restoration and then encapsulated by PCGS. I doubt there are many collectors who would risk a $54k investment on a home dipping session. >>
>>
Ditto. No chance this was submitted in the holder for "conservation", no chance PCGS would dip it under those circumstances, and no chance they would upgrade it if they knew it was submitted in an N58 holder.
It's also a shame when someone buys a historic beach cottage and tears it down and puts up a condo. It's a shame when an original old car gets restored. It's a shame when a patinated old painting or piece of antique furniture gets conserved. It's a shame when antique metal toys get sanded and repainted. shame shame shame.
But it's really difficult to make people do what you think they "should" do with own bought and paid-for property.
The NGC AU58 had at best 2/3 luster and obvious knee rub among other issues. No way that's mint state even if the dipping tends to "diffuse" all those faults away from a grader's eye.
The PCGS AU58+ looks to be a far better coin, and one I'd probably have no problem calling a MS61 as it appears to have nearly fully mint luster and at most the most minute rub. These days even MS64 seated halves sometimes have huge rub on the leg....even if I find that rather annoying.
The colorful 1870-cc above must be the MS63 (or better) finest known. I'd grade it the same regardless of the 2 photos shown. That doesn't change the luster remaining.
Ditto. No chance this was submitted in the holder for "conservation", no chance PCGS would dip it under those circumstances, and no chance they would upgrade it if they knew it was submitted in an N58 holder.
I can't tell if you're laughing with me or at me, but I'll assume the latter. all that and yet the coin is STILL in a PCGS MS61 holder. after all the chatroom analyzation, after all the online grading of pictures, after all the "experts" have weighed in and pontificated about what a coin should/shouldn't look like, after all the chest thumping and back slapping the coin is STILL in a PCGS MS61 holder.
This 1796 No Stars quarter eagle was graded AU-50 in an NGC holder.
Then it was cracked out, cleaned and submitted to PCGS when it got an AU-58.
I took both sets of photographs, and an expert dealer who has handled this piece at least twice, confirmed to me that the piece had been cleaned.
Retired dealer and avid collector of U.S. type coins, 19th century presidential campaign medalets and selected medals. In recent years I have been working on a set of British coins - at least one coin from each king or queen who issued pieces that are collectible. I am also collecting at least one coin for each Roman emperor from Julius Caesar to ... ?
<< <i>Good question BidAsk, I don't have the coin, in hand. edit to add: Am not , nor have I ever been a proponent of dipping. (the smell is atrocious). Have seen it done , have done it, and do believe it "helps" plenty of good men achieve "better" prices in the market for plenty of "ugly' coins. I hate to say that, but there are ugly ones in the mix that can benefit…. (it's just not MY field)
But that doesn't mean EVERY coin should be dipped, because they're ugly toned, or tarnished. In essence, there's a fine line between brilliant and idiot savant. >>
If "the smell is atrocious", how did it get past the PCGS sniffers (or do they not smell their own?)?
This 1796 No Stars quarter eagle was graded AU-50 in an NGC holder.
Then it was cracked out, cleaned and submitted to PCGS when it got an AU-58.
I took both sets of photographs, and an expert dealer who has handled this piece at least twice, confirmed to me that the piece had been cleaned. >>
I don't disagree with your assessment, although it appears the marks which feature prominently on the second set of images appear to be present on the first set. Based solely on those pictures I can't see any alteration besides lighting.
<< <i>Good question BidAsk, I don't have the coin, in hand. edit to add: Am not , nor have I ever been a proponent of dipping. (the smell is atrocious). Have seen it done , have done it, and do believe it "helps" plenty of good men achieve "better" prices in the market for plenty of "ugly' coins. I hate to say that, but there are ugly ones in the mix that can benefit…. (it's just not MY field)
But that doesn't mean EVERY coin should be dipped, because they're ugly toned, or tarnished. In essence, there's a fine line between brilliant and idiot savant. >>
If "the smell is atrocious", how did it get past the PCGS sniffers (or do they not smell their own?)? >>
You're asking the wrong guy. I'm here for the lesson, and having fun with my coins. Most of which don't measure up , and with few here who come down to the level which I endeavor most… That's the STREET level.
P.S. I don't subscribe to dipping or stripping in public or private. (coins , that is). On the other hand, if I wasn't here, I'd be ATS saying the same thing.
<< <i>Good question BidAsk, I don't have the coin, in hand. edit to add: Am not , nor have I ever been a proponent of dipping. (the smell is atrocious). Have seen it done , have done it, and do believe it "helps" plenty of good men achieve "better" prices in the market for plenty of "ugly' coins. I hate to say that, but there are ugly ones in the mix that can benefit…. (it's just not MY field)
But that doesn't mean EVERY coin should be dipped, because they're ugly toned, or tarnished. In essence, there's a fine line between brilliant and idiot savant. >>
If "the smell is atrocious", how did it get past the PCGS sniffers (or do they not smell their own?)? >>
You're asking the wrong guy. I'm here for the lesson, and having fun with my coins. Most of which don't measure up , and with few here who come down to the level which I endeavor most… That's the STREET level.
P.S. I don't subscribe to dipping or stripping in public or private. (coins , that is). On the other hand, if I wasn't here, I'd be ATS saying the same thing. >>
My question was not meant to be directed at you, but you did mention that dipping smells atrocious. I thought our hosts 'new gizmo' was supposed to detect such "doctoring" and to go along with other suggestions made here (the coin was sent into PCGS to be 'conserved') I inferred that "this doggy didn't smell his own mess first".
RonHedden: <<Oh dear, that is such a shame. There was just nothing wrong with the patina it had. I would not bid on the coin in its present state, though. Sorry. The dipper-stripper should be put in the stockade and pelted with Seated halves until dead.>>
This is an exceptional thread. It is important, though, to reflect upon logical and cultural reasons as to why dipping is harmful to coins, and not just express emotions.
MS71: <I see a fair amount of CAC coins that I can't help but see as recently dipped, sometimes very recently, to my eye. I guess it works under the "market acceptable" philosophy, but it completely turns me off on the coin>>
TomB: <<The TPGs did not start this problem and as long as the TPGs largely reflect what is acceptable in the broader market ...>>
Yes and no, it depends upon how the "broader market" is defined. When PCGS was founded, it probably did not occur to the founders that PCGS would become so popular and widely accepted by collectors. The intention then was to certify coins that would be sold non-collecting investors and to the general public, often to people who know little about coins.
Most (not all) sophisticated collectors have always preferred naturally toned coins. Morgan Dollars, Walkers and generic gold coins, in the 1980s and in the present, are heavily marketed to people who know little about coins or about the culture of coin collecting. I wonder if, essentially, grading criteria that was primarily formulated for Morgans, Walkers and generic gold coins (to be telemarketed) was adopted for all classic U.S. coins?
SethChandler: <<Lots of different viewpoints. Thats what this board is all about>>
While there are unusual cases where the benefits of a dipping outweigh the harm done, if a coin with decades of natural toning is dipped, much of the history and personality of the coin is destroyed. Some knowledgeable people who would like to own the coin in the future are being harmed. Indeed, when a really rare coin is dipped, many people in the coin collecting community may be harmed. Such coins are important to people in addition to those who own them.
This is especially true hen a coin that was formerly in the Garrett, Eliasberg, or Norweb Family collections is dipped; the legacy of an epic collection is harmed. The traditions and history of coin collecting are impaired. too.
pmac wrote: My question was not meant to be directed at you, but you did mention that dipping smells atrocious. I thought our hosts 'new gizmo' was supposed to detect such "doctoring" and to go along with other suggestions made here (the coin was sent into PCGS to be 'conserved') I inferred that "this doggy didn't smell his own mess first".
EZest, for example, contains thiourea and sulfuric acid. It strips off tarnish and a thin layer of metal as well. When used on a coin, a sulphurous odor may be detected; this does not linger once the dip has been rinsed off. I believe that the sniffer is supposed to detect substances adherent to the coin itself.
<< <i>Good question BidAsk, I don't have the coin, in hand. edit to add: Am not , nor have I ever been a proponent of dipping. (the smell is atrocious). Have seen it done , have done it, and do believe it "helps" plenty of good men achieve "better" prices in the market for plenty of "ugly' coins. I hate to say that, but there are ugly ones in the mix that can benefit…. (it's just not MY field)
But that doesn't mean EVERY coin should be dipped, because they're ugly toned, or tarnished. In essence, there's a fine line between brilliant and idiot savant. >>
If "the smell is atrocious", how did it get past the PCGS sniffers (or do they not smell their own?)? >>
You're asking the wrong guy. I'm here for the lesson, and having fun with my coins. Most of which don't measure up , and with few here who come down to the level which I endeavor most… That's the STREET level.
P.S. I don't subscribe to dipping or stripping in public or private. (coins , that is). On the other hand, if I wasn't here, I'd be ATS saying the same thing. >>
My question was not meant to be directed at you, but you did mention that dipping smells atrocious. I thought our hosts 'new gizmo' was supposed to detect such "doctoring" and to go along with other suggestions made here (the coin was sent into PCGS to be 'conserved') I inferred that "this doggy didn't smell his own mess first". >>
The term "sniffer" as applied to the PCGS gizmo is used in the figure of speech sense and does not rely on detection due to some odoriferous property of something on the coin.
PMac: <<... dipping smells atrocious. I thought our hosts 'new gizmo' was supposed to detect such "doctoring" and to go along with other suggestions made here ... I inferred that "this doggy didn't smell his own mess first". >>
Kaz: <<EZest, for example, contains thiourea and sulfuric acid. It strips off tarnish and a thin layer of metal as well. When used on a coin, a sulphurous odor may be detected; this does not linger once the dip has been rinsed off. I believe that the sniffer is supposed to detect substances adherent to the coin itself.>>
Even after a substance is "rinsed off," it is likely that microscopic quantities of it remain. Depending upon how the sniffer is programmed and adjusted, it is extremely likely that it can detect that a coin was dipped. This is largely an academic point, however, as it is the policy of PCGS that dipping is very much acceptable. Although I regard dipping as harmful and I honestly believe that a majority of sophisticated collectors regard dipping as harmful, it seems that PCGS does not regard dipping as harmful. IMO, though, there are rare cases where the benefits of dipping outweigh the harm done.
The contributors to this thread should understand the reality that PCGS, NGC and CAC have graded a large number of bright white 19th century, obviously dipped, coins as 66 or 67! This is especially true of Morgan Dollars.
In other contexts, I have pointed out that dipping, though harmful, is not particularity deceptive. When PCGS grades a coin that has been dipped not long ago, they know that it has been dipped. Coin doctoring involves practices that are deceptive, practices which often fool advanced experts.
Comments
<< <i>
<< <i>right.................. >>
Jeeze Louise, what did the coin docs do before PCGS started conserving? I expect there are plenty of em out there as good as if not better than the one/s at PCGS. WE don't know who bought the coin or who conserved it/had it conserved, but does it really matter? >>
I know who made it and the owner conserved it personally, but I'm not sure why it matters.
<< <i>
<< <i>
<< <i>right.................. >>
Jeeze Louise, what did the coin docs do before PCGS started conserving? I expect there are plenty of em out there as good as if not better than the one/s at PCGS. WE don't know who bought the coin or who conserved it/had it conserved, but does it really matter? >>
I know who made it and the owner conserved it personally, but I'm not sure why it matters. >>
I was gonna say that this is the much more likely scenario. Dealers dip coins all of the time and send them in successfully with little to NO cost.
A guy I met at a show, once, told me that he dips EVERYTHING before sending it in, even if it's stone white!! How twisted is that??!! I cringed at the thought of it!!
Sometimes, it’s better to be LUCKY than good. 🍀 🍺👍
My Full Walker Registry Set (1916-1947):
https://www.ngccoin.com/registry/competitive-sets/16292/
Latin American Collection
World Collection
British Collection
German States Collection
<< <i>
<< <i>
<< <i>right.................. >>
Jeeze Louise, what did the coin docs do before PCGS started conserving? I expect there are plenty of em out there as good as if not better than the one/s at PCGS. WE don't know who bought the coin or who conserved it/had it conserved, but does it really matter? >>
I know who made it and the owner conserved it personally, but I'm not sure why it matters. >>
It doesn't really, but I think it's naive to believe that just because PCGS started advertising dipping coins, that the big crackout gurus and coin docs have just suddenly quit doing it. I suppose the telltale thing here is that had a coin doc done it, it would have been done within days of being sold at Heritage in 2012.
<< <i>That's sad, one more original coin bites the dust. I m a little surprised it didn't Genuine. >>
I agree - it was horrid before the dip. What was NGC thinking?
Leo
The more qualities observed in a coin, the more desirable that coin becomes!
My Jefferson Nickel Collection
Sad, indeed.
FWIW I think the coin was unattractive before and horrendous after.
Latin American Collection
<< <i>FWIW I think the coin was unattractive before and horrendous after. >>
Experience the World through Numismatics...it's more than you can imagine.
<< <i>
<< <i>Frankly when a 145 YO coin comes in the door looking like it was just struck that morning, it shouldn't raise any eyebrows?
I highly doubt that the coin in question was cracked out of the holder, dipped and submitted to PCGS for grading, you're smarter than that!! more than likely it was submitted to PCGS in the NGC holder for restoration and then encapsulated by PCGS. I doubt there are many collectors who would risk a $54k investment on a home dipping session. >>
Ditto. No chance this was submitted in the holder for "conservation", no chance PCGS would dip it under those circumstances, and no chance they would upgrade it if they knew it was submitted in an N58 holder.
Coin Rarities Online
It's also a shame when someone buys a historic beach cottage and tears it down and puts up a condo. It's a shame when an original old car gets restored. It's a shame when a patinated old painting or piece of antique furniture gets conserved. It's a shame when antique metal toys get sanded and repainted. shame shame shame.
But it's really difficult to make people do what you think they "should" do with own bought and paid-for property.
Liberty: Parent of Science & Industry
The PCGS AU58+ looks to be a far better coin, and one I'd probably have no problem calling a MS61 as it appears to have nearly fully mint luster and at most the most minute rub. These days even
MS64 seated halves sometimes have huge rub on the leg....even if I find that rather annoying.
The colorful 1870-cc above must be the MS63 (or better) finest known. I'd grade it the same regardless of the 2 photos shown. That doesn't change the luster remaining.
I can't tell if you're laughing with me or at me, but I'll assume the latter. all that and yet the coin is STILL in a PCGS MS61 holder. after all the chatroom analyzation, after all the online grading of pictures, after all the "experts" have weighed in and pontificated about what a coin should/shouldn't look like, after all the chest thumping and back slapping the coin is STILL in a PCGS MS61 holder.
This 1796 No Stars quarter eagle was graded AU-50 in an NGC holder.
Then it was cracked out, cleaned and submitted to PCGS when it got an AU-58.
I took both sets of photographs, and an expert dealer who has handled this piece at least twice, confirmed to me that the piece had been cleaned.
Experience the World through Numismatics...it's more than you can imagine.
<< <i>Good question BidAsk, I don't have the coin, in hand.
edit to add: Am not , nor have I ever been a proponent of dipping. (the smell is atrocious).
Have seen it done , have done it, and do believe it "helps" plenty of good men achieve "better" prices in the market for plenty of "ugly' coins.
But that doesn't mean EVERY coin should be dipped, because they're ugly toned, or tarnished.
In essence, there's a fine line between brilliant and idiot savant. >>
If "the smell is atrocious", how did it get past the PCGS sniffers (or do they not smell their own?)?
<< <i>I still point to this sorry tale.
This 1796 No Stars quarter eagle was graded AU-50 in an NGC holder.
Then it was cracked out, cleaned and submitted to PCGS when it got an AU-58.
I took both sets of photographs, and an expert dealer who has handled this piece at least twice, confirmed to me that the piece had been cleaned. >>
I don't disagree with your assessment, although it appears the marks which feature prominently on the second set of images appear to be present on the first set. Based solely on those pictures I can't see any alteration besides lighting.
<< <i>Any suggestions for cleaning puke out of a keyboard? >>
``https://ebay.us/m/KxolR5
<< <i>
<< <i>Good question BidAsk, I don't have the coin, in hand.
edit to add: Am not , nor have I ever been a proponent of dipping. (the smell is atrocious).
Have seen it done , have done it, and do believe it "helps" plenty of good men achieve "better" prices in the market for plenty of "ugly' coins.
But that doesn't mean EVERY coin should be dipped, because they're ugly toned, or tarnished.
In essence, there's a fine line between brilliant and idiot savant. >>
If "the smell is atrocious", how did it get past the PCGS sniffers (or do they not smell their own?)?
You're asking the wrong guy. I'm here for the lesson, and having fun with my coins. Most of which don't measure up , and with few here who come down to the level which I endeavor most… That's the STREET level.
P.S. I don't subscribe to dipping or stripping in public or private. (coins , that is). On the other hand, if I wasn't here, I'd be ATS saying the same thing.
``https://ebay.us/m/KxolR5
<< <i>
<< <i>
<< <i>Good question BidAsk, I don't have the coin, in hand.
edit to add: Am not , nor have I ever been a proponent of dipping. (the smell is atrocious).
Have seen it done , have done it, and do believe it "helps" plenty of good men achieve "better" prices in the market for plenty of "ugly' coins.
But that doesn't mean EVERY coin should be dipped, because they're ugly toned, or tarnished.
In essence, there's a fine line between brilliant and idiot savant. >>
If "the smell is atrocious", how did it get past the PCGS sniffers (or do they not smell their own?)?
You're asking the wrong guy. I'm here for the lesson, and having fun with my coins. Most of which don't measure up , and with few here who come down to the level which I endeavor most… That's the STREET level.
P.S. I don't subscribe to dipping or stripping in public or private. (coins , that is). On the other hand, if I wasn't here, I'd be ATS saying the same thing. >>
My question was not meant to be directed at you, but you did mention that dipping smells atrocious. I thought our hosts 'new gizmo' was supposed to detect such "doctoring" and to go along with other suggestions made here (the coin was sent into PCGS to be 'conserved') I inferred that "this doggy didn't smell his own mess first".
RonHedden: <<Oh dear, that is such a shame. There was just nothing wrong with the patina it had. I would not bid on the coin in its present state, though. Sorry. The dipper-stripper should be put in the stockade and pelted with Seated halves until dead.>>
This is an exceptional thread. It is important, though, to reflect upon logical and cultural reasons as to why dipping is harmful to coins, and not just express emotions.
MS71: <I see a fair amount of CAC coins that I can't help but see as recently dipped, sometimes very recently, to my eye. I guess it works under the "market acceptable" philosophy, but it completely turns me off on the coin>>
TomB: <<The TPGs did not start this problem and as long as the TPGs largely reflect what is acceptable in the broader market ...>>
Yes and no, it depends upon how the "broader market" is defined. When PCGS was founded, it probably did not occur to the founders that PCGS would become so popular and widely accepted by collectors. The intention then was to certify coins that would be sold non-collecting investors and to the general public, often to people who know little about coins.
Most (not all) sophisticated collectors have always preferred naturally toned coins. Morgan Dollars, Walkers and generic gold coins, in the 1980s and in the present, are heavily marketed to people who know little about coins or about the culture of coin collecting. I wonder if, essentially, grading criteria that was primarily formulated for Morgans, Walkers and generic gold coins (to be telemarketed) was adopted for all classic U.S. coins?
SethChandler: <<Lots of different viewpoints. Thats what this board is all about>>
While there are unusual cases where the benefits of a dipping outweigh the harm done,
if a coin with decades of natural toning is dipped, much of the history and personality of the coin is destroyed. Some knowledgeable people who would like to own the coin in the future are being harmed. Indeed, when a really rare coin is dipped, many people in the coin collecting community may be harmed. Such coins are important to people in addition to those who own them.
This is especially true hen a coin that was formerly in the Garrett, Eliasberg, or Norweb Family collections is dipped; the legacy of an epic collection is harmed. The traditions and history of coin collecting are impaired. too.
Natural Toning, Dipping and Coin Doctoring, Part 1
Understanding Classic U.S. Coins and Building Excellent Coin Collections, Part 2: Dipped Coins
The Dazzling Collecting Journey of Dr. Steven Duckor
Natural Toning, Dipping and Coin Doctoring, Part 3
My question was not meant to be directed at you, but you did mention that dipping smells atrocious. I thought our hosts 'new gizmo' was supposed to detect such "doctoring" and to go along with other suggestions made here (the coin was sent into PCGS to be 'conserved') I inferred that "this doggy didn't smell his own mess first".
EZest, for example, contains thiourea and sulfuric acid. It strips off tarnish and a thin layer of metal as well. When used on a coin, a sulphurous odor may be detected; this does not linger once the dip has been rinsed off. I believe that the sniffer is supposed to detect substances adherent to the coin itself.
<< <i>
<< <i>
<< <i>
<< <i>Good question BidAsk, I don't have the coin, in hand.
edit to add: Am not , nor have I ever been a proponent of dipping. (the smell is atrocious).
Have seen it done , have done it, and do believe it "helps" plenty of good men achieve "better" prices in the market for plenty of "ugly' coins.
But that doesn't mean EVERY coin should be dipped, because they're ugly toned, or tarnished.
In essence, there's a fine line between brilliant and idiot savant. >>
If "the smell is atrocious", how did it get past the PCGS sniffers (or do they not smell their own?)?
You're asking the wrong guy. I'm here for the lesson, and having fun with my coins. Most of which don't measure up , and with few here who come down to the level which I endeavor most… That's the STREET level.
P.S. I don't subscribe to dipping or stripping in public or private. (coins , that is). On the other hand, if I wasn't here, I'd be ATS saying the same thing. >>
My question was not meant to be directed at you, but you did mention that dipping smells atrocious. I thought our hosts 'new gizmo' was supposed to detect such "doctoring" and to go along with other suggestions made here (the coin was sent into PCGS to be 'conserved') I inferred that "this doggy didn't smell his own mess first". >>
The term "sniffer" as applied to the PCGS gizmo is used in the figure of speech sense and does not rely on detection due to some odoriferous property of something on the coin.
PMac: <<... dipping smells atrocious. I thought our hosts 'new gizmo' was supposed to detect such "doctoring" and to go along with other suggestions made here ... I inferred that "this doggy didn't smell his own mess first". >>
Kaz: <<EZest, for example, contains thiourea and sulfuric acid. It strips off tarnish and a thin layer of metal as well. When used on a coin, a sulphurous odor may be detected; this does not linger once the dip has been rinsed off. I believe that the sniffer is supposed to detect substances adherent to the coin itself.>>
Even after a substance is "rinsed off," it is likely that microscopic quantities of it remain. Depending upon how the sniffer is programmed and adjusted, it is extremely likely that it can detect that a coin was dipped. This is largely an academic point, however, as it is the policy of PCGS that dipping is very much acceptable. Although I regard dipping as harmful and I honestly believe that a majority of sophisticated collectors regard dipping as harmful, it seems that PCGS does not regard dipping as harmful. IMO, though, there are rare cases where the benefits of dipping outweigh the harm done.
The contributors to this thread should understand the reality that PCGS, NGC and CAC have graded a large number of bright white 19th century, obviously dipped, coins as 66 or 67! This is especially true of Morgan Dollars.
In other contexts, I have pointed out that dipping, though harmful, is not particularity deceptive. When PCGS grades a coin that has been dipped not long ago, they know that it has been dipped. Coin doctoring involves practices that are deceptive, practices which often fool advanced experts.
Understanding Classic U.S. Coins and Building Excellent Coin Collections, Part 2: Dipped Coins
The Dazzling Collecting Journey of Dr. Steven Duckor
Natural Toning, Dipping and Coin Doctoring, Part 3
The Formal Introduction of the PCGS 'Coin Sniffer' at the PCGS Luncheon