Results of cleaning experiment - "Q-tips" and Acetone on Gold

zeebob

I've found acetone pretty good for PVC, but I've noticed that to really get PVC or other gunky haze off a coins surface just a soak doesn't always work. I've read and been told any mechanical rubbing will leave hairlines.

I use a binocular microscope and two 20 watt halogen desk lamps for illumination. I can adjust the magnification from 3.5x to 40x. I usually adjust the magnification so the coin fills the filed of view (7x - 10x or so)

I played with some acetone wetted q-tips and some old silver coins. If you press hard enough I can see hairlines, but you have to press pretty hard.

I played with some acetone wetted q-tips and some MS state quarters. Those are tough as nails. I didn't see any hairlines.

So I figured I'd have a go at the softest metal - gold.

I bought a VERY hazed over (PVC was my suspicion) krugerand. I gave it 4 rounds of soaking and wetted q-tip (light touch) treatment over about six days. The acetone soaks weren't doing jack for the haze, but the wetted q-tip treatment worked the gunk right off the surface. Fields first, protected areas took multiple treatments.

At the end, to the naked eye, the coin looked great. Under the microscope, the coin looked hairline free. (and gunk free) So I decided I'd let our hosts have a go at grading it. I figured it would .92 if I messed up the surface.

Don't bother to blast me for slabbing bullion. I know you don't get more bullion than krugerands. I sent it in as a test of my cleaning (I like to think of them as conservation) techniques.

You can blast me for cleaning coins. We all have to draw that line for ourselves. Apparently removing harmful gunk with acetone and wetted q-tip is where I draw my line. I hope to expand to mineral oil and olive oil for copper and bronze soon.

Anyway, PCGS slabbed the thing as MS66.

I did not "roll the wetted q-tip like a tire" across the surface. Using a very light touch, I rolled the q-tip in the opposite direction of travel (like a tire skidding on ice). I found that scrubbing this-way-and-that is okay as well. But the trick is to use a very light touch. Always keep the surface wet. Work with a mircoscope so you can see. And use a Q-tip that is not Q-tip brand. I use cotton swabs that are built for electronics. They have a wood stick and NO GLUE. The glue on regular swaps melts in acetone. Plastic stick don't hold up so well either. Both glued cotton and plastic stick swabs leave more gunk on the surface than they remove.

There you have it. More information for the collective pool. Cheers.



What the heck and I going to do with a slabbed krugerand?

JoesMaName

Good read, thanks for the post/info.

BBQnBLUES

<<What the heck and I going to do with a slabbed krugerand?>>

Please add me to this Generous Giveaway

Bailathacl

If you happen to have a picture....

zeebob

Sorry, when the coin comes back, I'll take a photo and post to the thread - but I gotta say, the krugerand looks like every other krugerand, just a lump of gold with a funny deer looking thing on it.

I should have been more careful documenting my results. Next experiment, I'll have before and after shots.

Bailathacl

I'm about to put some gentle "muscle" to the Q-Tips on an ex-mounted 1861 Spanish 40 Reales piece, with acetone only... so I'm heartened by your experience.

BTW I think the funny-looking deer is a Thompson's Gazelle (a "Tommy" in local speak), but I've been wrong before... today....

satootoko

<< <i>What the heck and I going to do with a slabbed krugerand? >>

Frame it and hang it on the wall.

Silvereagle82

I may be wrong but I don't think gold is affected by PVC ..... so it must of been some other type contaminate

IloiloKano

Thanks for sharing that zeebob. I have a few bronzes that I have been too worried about hairlining to try that myself. Most of them, including the one I received today, benefit from the use of acetone, and I have achieved pretty satisfactory results with the glass covered butter dish that I use for soaking coins in acetone, (combined with gently tamping with a cotton ball while sitting in the solution). I did that this afternoon with the coin below. Top images are from the seller's pics, and bottom images are mine after treatment with acetone, then with olive oil to remove any residue, as well as for preservation. It's now sitting in a two by two, awaiting shipment for certification (this summer).

In the future, I might be a bit more aggressive, thanks to your posting of experimental results. Thank you again for sharing your experience. Good job!



Edited to add... The above coin received certification by PCGS as MS63 BN. PCGS Certification #14643152

determined

Very interesting experiment! Thanks for sharing zeebob!

1jester

Bob, thanks for your scientific analysis! I was waiting for someone to put the "acetone soak alone" and "rolling q-tip" procedures to a test to determine their (lack of) efficacy on conserving (let's use this term lest others accuse of "cleaning" coins). I have used the olive oil treatment on hundreds upon hundreds of coins, and as I've written elsewhere, I've also used an acetone bath on virtually every coin I've come into contact with to ensure there's none of the mortal coin enemy PVC left. Now, in all my travels (travails?), I've learned that an acetone soak alone usually won't get the PVC (and other junk, to a greater extent) off the coins. What's necessary is some kind of mechanical rubbing. And as you allude to, one of the most important procedures is to keep the coin surface wet (or under the acetone completely) while you "work" or "massage" the surface with some kind of instrument. I've tried q-tips (also with wooden handles, not plastic), balls of cotton, soft cotton cloth, toothbrushes (won't work with acetone, but with olive oil; ultra soft brushes are available for coins with wooden handles and camel's hair), rose thorns (usually for getting stubborn verdigris off coins during an olive oil treatment), and my fingers. I've found that using my fingers alone, while the coin is under acetone, works fine in most cases; I simply rub the coin's surface and then move it to the other bowls of successively cleaner acetone till I'm done. This usually suffices, except where there's been lots of PVC contamination, in which case I have to use a soft cloth or better, the brush, to complete my mission by getting in the areas protected by the devices. Results (if you're careful) - clean, conserved coins with no hairlines (visible under 16 x loupe). Plenty of my conserved coins have been slabbed by the big 4 TPGs (ICG being the 4th).

Thanks again for your writeup and experimentation for the good of the numismatic world. The scourge of PVC use might not be stopped, but it can be ameliorated by stopping it on the coins we individually own. The conservation of coins is unfortunately necessary due to the unscrupulous use of PVC products over the decades. Unless one is absolutely certain a coin has never been subjected to the horrors of this poison even for a few minutes in its life, it deserves an acetone bath and conservation.

Preussen

Thanks for sharing your success. While I in no way advocate “messing” with coins just for the sake of messing with them, I do believe that there are times that careful conservation is beneficial and even necessary to prevent further deterioration.

Here is one that I consider my greatest conservation success: -Preussen

Before:


After - crud removed but original toning and luster remain undisturbed. (now slabbed NGC MS66)

zeebob

Wow, you guys posted some nice images! Thank you.

The comment, "I may be wrong but I don't think gold is affected by PVC ..... so it must of been some other type contaminate," is for the most part correct.

Gold is pretty non-reactive. So PVC usually doesn't corrode the surface.

However PVC will coat the surface of gold just like any other coin.

I don't know for sure that the coin I had was PVC contaminated, but it looked like it. And I know when the guy (a relative of mine) bought the coin and PVC flips were pretty common (mid '80s). When he handed it to me it was bare (so for sure it had finger grease). Don't ask how much I overpa

If I understand what I read on the web, many gold coins are alloyed with another metal and PVC can cause corrosion of alloyed coins. I gather the .90 coins with "copper spots" are most susceptible to corrosion where copper atoms are on the surface.

That krugerand I had was (I think) 90% gold (no copper spots).

krueger

Nice pickup, but am concerned with your statement almost as a question.

<"then with olive oil to remove any residue, as well as for preservation">

After conservation and for preservation the copper collectors I believe use products like "care", "coin care" or the old "blue ribbon coin conditioner" all containing a lubricant applying with a camel hair brush. Olive oil is mostly oleic acid, I am not sure how long it would take if left on the surfaces to start to eat at the surfaces.

maybe someone could enlighten us.

Krueger

IloiloKano

krueger, thanks for bringing that matter up. I admit that I was quite concerned when I first read your comment. So I did some research, and here is what I discovered.

Extra Virgin olive oil is virgin olive oil which has a free acidity, expressed as oleic acid, of not more than 0.8 grams per 100 grams (0.8%), and the other characteristics of which correspond to those fixed for this category.

Refined olive oil is the olive oil obtained from virgin olive oils by refining methods which do not lead to alterations in the initial glyceridic structure. It has a free acidity, expressed as oleic acid, of not more than 0.3 grams per 100 grams (0.3%) and its other characteristics correspond to those fixed for this category in this standard.

The olive oil that I have been using states on its label that it is Refined Olive Oil, so I expect its particular acidity percentage is on the order of 0.3%.

In an article on Lubrication and Lubricants, I found reference to acidity of less than 0.26% being described as "negligible", and the article also contained a description of how oleic acid reacted with certain metals. In each case, the reaction was in the presence of water, oleic acid and extreme heat.

All fluid is acid, base or perfectly neutral, and simply because a fluid is acidic, that doesn't mean it is significantly acidic. If it was a base, it would also be reactive, so the only perfect solution would be absolutely neutral, which you will only find in a laboratory. Even distilled water will not be perfectly neutral, since it won't be perfectly distilled, because to do so would make it prohibitively expensive.

I suspect I have been lucky, because there are olive oils on the market having a significantly higher acidity percentage, and because I have always used it such that practically no oil remains on the coin, (though I suspect a very small amount does remain). I have used it primarily as a means of displacing any contaminants remaining after the acetone treatment, which contaminants I expect to be much more harmful long term. Also, the acidity percentage in the olive oil I have used is very close to what the article's author described as negligible, and water plus extreme heat never is a factor in my usage. Even so, I think I will look into using mineral oil in the future, since what I discovered about it is that mineral oils do not contain free fatty acids found in vegetable oils. I will also take greater care in ensuring practically all oil is removed is the process. I still will use it, since I believe the effect it has on displacing other contaminants is noticeable, as I have seen on more than one occasion such desirable effect, but I will do so with much more care after having read your expressed concerns.

edited to add...

<< <i>products like "care", "coin care" or the old "blue ribbon coin conditioner" >>

I will also look into possibly using one of the products you mentioned.

krueger

IloiloKano,

Good research job! Keep that up, and NCS will be looking to offer you a job!
I guess it doesn't look like what you are doing is any problem at all. Sorry I got you worried.

Krueger

IloiloKano

zeebob,

I tried out your technique with a low value coin, and I have before/after pictures that appear to confirm your experimental results. The only modification to your procedure was that I used a cotton ball to rub the acetone over the surface, vice your use of a cotton tipped applicator. To post the largest images would be overkill, but even with the individual images at 1300 x 1300 pixels, I could not detect any hairlines. The images I am posting are each 400 x 400 pixels combined into a single 800 x 800 picture, but I believe the results are clearly seen. Note how the PVC residue had actually hidden details in the eagle feathers, which became clearer after treatment. From now on, I won't be so hesitant to apply slight pressure when using acetone to remove PVC residue. I didn't get it all, but the coin's value didn't warrant spending more time to get every single bit of residue.

Thanks again for posting your experimental results for our benefit.

DeutscherGeist

How about giving proof silver coins that same treatment? Proof silver coins are so sensitive and if dipping them in acetone might not take off all contaminants, is a little finger rubbing while the coin is immersed in actone OK or will it cause lines?

I have to give all my coins an acetone bath just because I do not know where they have been and it is a precautionary measure. You all described MINT STATE type coins, but I wonder if these techniques apply to PROOF type coins.

IloiloKano

I absolutely would NOT use, nor would I recommend using, the same technique on proof coins.

1jester

<< <i>I absolutely would NOT use, nor would I recommend using, the same technique on proof coins. >>



I agree. I have screwed up way too many (not that many in number, in fact, but any is too many!) proof coins by trying to conserve them using a contact method of acetone treatment. No matter how lightly one rubs on a proof coin, it will leave marks, scratches and hairlines. I'm so sensitive to this issue that I will no longer buy proof coins that aren't mint-sealed, because either there's a probability they've come in contact with PVC or fingerprints, etc, or I'll damage them by trying to remove those contaminants. So I don't buy them anymore unless they're sealed or guaranteed to be free from contaminants.

DeutscherGeist

This is what I thought. Proof coins are too sensitive to rub on. How about just dipping them in acetone without rubbing? I guess that should be OK, but it would really get very little contaminants off. Better than nothing though.

Jester,

I am with on just buying proof silver coins that are sealed in original packaging. Some folks on these boards thought I was strange when I always inquired about fingerprints on proof coins. You seem to understand that if a coin has been in existence for 25 years, it could have had its capsule opened by an unwitting casual collector and handled. Some capsules from national mints are not sealed, meaning if you don't know its history, it could have been handled.

I once bought Canadian Olympic silver proofs. I noticed later they had fingerprints on them. That's when I learned my lesson that capsules are not always the sealed type even when from a national mint. And its not stupid to ask a seller on ebay if a proof coin has fingerprints on it or not. Because if you don't ask and it turns out it has it, you will have fewer legs to stand on. Plus, sellers are not going to lie about fingerprints if you point blank ask about them because then you have an easy paypal case against them if they do say there are no fingerprints and it turns out it does. Photos are not always good to determine such things, but if I discern fingerprints from a photo on ebay, I simply skip the auction.

I paid 14 euros each on the two Canadian Calgary Olympic silver proof coins (20 Canadian dollar denomination). I did not know that those coins would not be in the sealed capsules from the Canadian Mint like the Maple Leafs in sealed mylar. I bought a lot of Maple Leaf silvers throughout my lifetime because I always felt comfortable that they were sealed (Maple leafs might not be proof, but the surface still is too sensitive).

What can I do with my Olympic Canadians to get the fingerprint residue off the surface? Is there another type of dip that works real well in getting older fingerprints off the surface without any rubbing? I guess if nothing can be done, then at least I can rest a little easy knowing that what I paid for the coins is basically melt value or below (with current prices), so its not really a loss, just something unsightly for my Olympic collection.

Thanks jester, for affirming my suspicions on purchasing proof coins. I am not as experienced as most on here (my knowledge is in baseball cards), yet to be told that I am basically "stupid" for being concerned about fingerprints on proof coins---come on, who's the real ignorant one.

IloiloKano

<< <i>What can I do with my Olympic Canadians to get the fingerprint residue off the surface? >>


Talk to a local reputable jewelry dealer, (brick and mortar type, not one that is mainly online), and get information from them about a good sonic cleaner, which is typically used for cleaning gemstones, rings, bracelets and such. Tell him or her that you plan to use acetone, so it must not have plastic parts where contact with the solution is likely. See what he recommends. Though I have never purchased one, I believe there is a style that allows you to put a coin and acetone into a glass container, which is then subjected to micro vibrations, allowing the acetone to act in an optimum manner in removing most any residue.

They are not easily found available commercially, but a jeweler to whom I spoke years ago offered to purchase one for me (through his business supplier) with a very low mark-up. If memory serves, I believe it would have cost me about US$60. Though the one he used for his business cost him WAY more than that, it had a multitude of features I would never need.

Barring a sonic cleaner, a simple soak couldn't hurt, in my opinion.

DeutscherGeist

Oh, a sonic cleaner? We use those in the automotive world--larger units to clean the car parts.

A small sonic cleaner used for tiny items such as jewelry and coins should be about $100 or less depending on the features (as you alluded to as well). I was in the market for a sonic cleaner for car parts not too long ago, but one would need a big one to put on a table. They go for $400. I still want one, but I currently have a space problem to take advantage of a unit like that. I was initially thinking about using the sonic cleaner for both car parts and coins. I guess I can get more use out of a small one now since a large one is a distant dream for the time being.

With a small sonic cleaner, I can give all my coins a once over since the whole technique is so non-invasive. I assume it can even handle getting rid of some verdigris too.

Thanks for reminding me of the sonic cleaner. I guess my Canadian coins do have hope.

1jester

Geist, you give me too much credit! I merely think it's obvious that PVC kills coins and should never be used in numismatics, and have voiced that opinion on these boards (along with a few other stalwarts such as wybrit) for over 8 years that PVC is the scourge of numismatics and there's absolutely NO excuse for using it, ever. Period. I'm still amazed at how many people (including many dealers) give pathetic excuses for using it "short-term" or whatever. I had a nice collection of high grade DMPL Morgan dollars (including CC mint marked ones) along with other nice coins absolutely ruined by PVC. It was a huge loss to me. I saw the devastation wrought by the combination of PVC (and temperature and possibly salty atmosphere) on my coins; their surfaces looked like that of the moon with huge craters everywhere. The coins I had in inert (mylar) holders in the same atmosphere escaped without harm, even the red uncirculated copper coins. Thus began my education on the ravages of PVC. It has no place in numismatics, ever. And since we'll never know the history of most of the coins we buy, we cannot guarantee that they've never been in contact with PVC, thus all such coins need to be conserved in acetone in order to minimize the damage and remove the contaminants. As numismatists, we owe that to every coin we come into contact with, because even though often we can't see the PVC on the coin, if it's there, the chance or probability exists that it will harm the coin eventually.

So I'm in complete agreement with you on not even bothering with buying proof coins if they've been tampered with. It's not for me.

jt88

I have some copper coins that have green stuff on them. I put them with acetone for about two weeks. Nothing happened, the green stuff is still there. That makes think the green stuff might not be PVC. I used to clean silver and the green stuff gone very easily with silver. Anyone know hot to get rid of the green stuff on copper other than acetone? Thanks.

1960NYGiants

Try a long soak in extra virgin olive oil. Every couple if weeks us soft cotton swabs with thoil to remove the material that loosens up then replace the oil and soak some more. When done another bath in acetone to remove the oil.

There is also a product that one can buy from some of the on-line dealers called Coin-Care. Some of the Canadian large cent guys use WD-40. Apply - soak - acetone bathe.

Good luck.

jt88

I tried with olive oil before for about one hour. Looks like I will have to put it for couple weeks. Thanks a lot.