Coin conservation questions about drying after acetone and or distilled water soaking
350gn
Posts: 24 ✭
I've read every article I could find but am unsure of a few things when it comes to conservation.
Is it best to soak in acetone then distilled water, or vice versa? How much time is too much in either? What kind of surfaces are safe to then set the coin on to dry? Microfiber rags (like for cleaning your glasses)? Aluminum foil? Wax paper? Glass? I'm in a relatively dusty environment and have a box fan with a filter over it blowing on my workspace. Should I dry them at room temperature or get a hot plate or heating pad or something similar to dry them faster and make sure they're fully dessicated, or use an electric or gas oven? Do I need a new oven to make sure salt/oils from foods cooked in them don't then re-contaminate the coins? What temperature is safe? Should I wear gloves (nitrile)? or just wash my hands first. What kind of soap? Should I put on gloves then wash the gloves??
I have 2.5" mylar flips and an impulse sealer to seal them with once they are ready to be stored.
Have any institutions like the Smithsonian NNC, ANA Museum, etc put out detailed instructions that I've overlooked?
Comments
Unless they’re super rare, you’re overthinking it
. I like to grab some clean, Cotten gloves and place it into the acetone as-is. Then I leave it until it looks good, as acetone doesn’t damage coins. Then I take out, rinse and pat dry with a microfiber cloth. Hope this helps, and fix any mistakes I make. 
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If you are using pure acetone, after soaking the coin, you can just rinse it with fresh acetone and it will quickly evaporate. If you aren't sure how pure your acetone is, put a drop on a mirror or piece of glass and check the surface after the acetone evaporates to see if there is any residue left behind.
Worry is the interest you pay on a debt you may not owe.
"Paper money eventually returns to its intrinsic value---zero."----Voltaire
"Everything you say should be true, but not everything true should be said."----Voltaire
they are super rare
some copper
some silver
some cupronickel
I'd send them off for the pros to take care of but can't afford that
Welcome, so distilled water is the rinse after the acetone soak. Pat dry with lint free cloth. Handle by edge with clean fingers. Good luck. Peace Roy
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Be careful using acetone. I believe it can be absorbed through the skin and is toxic to the liver as well as vapor flammable.
You don’t have to rinse with water if your acetone is clean. Use the mirror test as stated above earlier in this thread. But a second rinse with fresh acetone should be done after soaking with acetone. Wear cotton gloves and place the coin on an old clean white cotton t-shirt and flip it over and place the coin on a dry spot. This will soak up any excess acetone and it will be dry in a few seconds. Don’t use polyester or the acetone will dissolve it and get goo on the coin, but cotton isn’t affected by acetone.
Mr_Spud
As said
1. Use pure acetone
2. Put on cotton gloves ( see what collectors use) and just pour the acetone and coin into glove
3. It going to evaporate fast fast fast!
4. Place the coin on correct type of cotton cloth
5. Remove gloves, wash hands Gloves will dry fast.
6. Only do this in a very well ventilated area. Extremely flammable
7. It happens fast and with practice on a less valuable coin you will become good at doing it.
8. Good luck
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Do not soak copper nickel in water or any solution more than about 20% water. Avoid soaking silver in water. Do not soak silver in ethyl alcohol unless pure. Soaking in 91% isopropyl or acetone requires as long as a week. Avoid warm water for rinsing or removing detergent but as a last step you can use running hot water. Dry on plush cotton towel, but pat don't rub. Flip coin and repeat patting.
I gotta ask. If they are SUPER RARE and you dont know how to do conservation on coins, why are you trying to clean them yourself?
If you dont have the money for professional cleaning now, just save up for awhile, then get it done. The coins arent going anywhere.
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This
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Yes. I think rinse with distilled water after acetone soak is a good idea. Acetone that one buys at the hardware store is not C.P., so there could be residue from it that stays on the coin after it evaporates. Acetone is totally miscible with water. Dry the coin after treatment by placing on soft, lint-free cloth. I like microfiber. Do no rubbing.
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Does the removed PVC evaporate with the acetone, or does it stay behind?
Doggedly collecting coins of the Central American Republic.
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The OP should know that though the initial soak in acetone can be for a minute, overnight, or several days, transferring to the rinse (acetone or DW) has to be very quick because acetone evaporates rapidly and could leave organic contaminants on the coin again. You will notice your coin also will be significantly cooled by the rapid evaporation.
Do it in a well-ventilated room or out of the house because the vapors are very flammable.
@350gn... Welcome aboard. Use 100% pure acetone only. Running hot water rinse. Cotton gloves. No ovens. If coins are truly rare (describe them here, you will get honest, accurate information), send them to TPG for conservation and slabbing. Save your money, it will be worth it - IF the coins are truly rare and valuable. Good luck, Cheers, RickO
It stays behind in the acetone and when the acetone evaporates it leaves green slime behind.
Yes, it will recontaminate the coin unless you do a second rinse with clean acetone. 3 or 4 rinsings with fresh acetone if heavily contaminated.
Mr_Spud
Note - For really valuable coins you can buy reagent grade acetone from Amazon. But regular hardware store acetone works fine if you do the mirror test. I once coordinated cleaning masking tape off the back of all the gold coins in the Charlotte mint museum and I supplied them with a gallon of reagent grade 100% acetone that came in a glass jug along with the glass jars with lids that were inert to acetone along with cotton cloths to dry the coins on and everything came out great. What I like to do with cotton cloths or white cotton t-shirts is to stretch them over top of an open cardboard box so the cotton is up in the air. It wicks away the acetone and you just turn the coin over and place it on a dry spot and it wicks away any acetone liquid real quickly. This way there is no need to even “pat” the coin and even less risk you’ll accidentally rub it. Here’s a picture of a small container of reagent grade 100% pure acetone.
Mr_Spud
Just by coincidence I have an Ike I found up in my attic a few weeks ago. It was in a box of old junk inside a blue plastic bag. It’s a box that I hadn’t opened since we hurriedly moved from Charlotte to California in 2007 when the place I was working at shut down and they offered me a transfer to their HQ out here in Cali. I have no recollection of where I got the Ike from, it was literally just laying loose inside of a used blue plastic bag like you would get if you bought a trinket somewhere. I’m currently about 1/4 the way done cleaning out old stuff in our attic one box at a time.
The coin was covered in some kind of plastic goo from the blue plastic bag it was in. The coin itself underneath the goo had turned golden in color. So I had it soaking in acetone for the last few weeks and it was ready for a rinse in fresh acetone today. So I made a pictorial record of how I did the rinse.
Here is the coin in the bottom of a small glass jar, I already threw out the dirty acetone it had been soaking in.
So I poured in enough fresh clean acetone to cover the coin and put its glass lid on so it wouldn’t evaporate. I twirled the closed glass container a little bit to make the acetone swirl around with the coin in it and then I set it down on a glass watch glass (not necessary, I just do this in case a drop of acetone leaks off the jar so it won’t stain my desk) and let it sit for about 15 minutes.
Then I dumped the coin and acetone out of the glass jar into my 2 drachm measuring beaker (you can use a shot glass) so the acetone goes to the bottom and the coin is suspended further up in the air.
Earlier I had prepared my cotton t-shirt stretched over an open box like this.
Then, I quickly but carefully pick up the coin with a cotton glove on my hand and place the coin on the white cotton t-shirt that I had previously put on the empty cardboard box.
Wait no more than a couple of seconds
And then quickly turn the coin over with your gloved hand and place the coin on the other side on a dry spot on the shirt.
Let it sit a minute and it’s done. You can put it in a saflips or whatever you are going to store it in. Here’s what the coin looks like. It came out well, I don’t like the dark line that some of the thickest part of the plastic goo left behind on the reverse below the bell all the way to under UNUM but at least there is no more gooey residue. The residue was all over the coin, but where the line is on the reverse was where the plastic bag had folded over on itself and made an even thicker line of goo.
So basically, you can see my entire technique above in the pictures. I do this on coins with PVC or other plastic residues, tape or glue, or if a coin was handled with bear hands/fingers before I store them in Saflips or put them in albums.
Mr_Spud
Stays behind. Hence the need to rinse with clean acetone. If PVC residue was volatile, you wouldn't need to use acetone in the first place.
I'm guessing "super rare" is a sliding scale.
How does one acquire "super rare" coins when one has no money?
I always did a double final rinse in acetone. The acetone from the hardware store was typically pure enough to yield a clean surface. Labels usually said 100% acetone, but I suspect there are trace impurities including water.
Anyway, some simple math. If I soak a coin in acetone to remove contaminants, the last steps would be a double rinse.
To err on the high side, let's assume that you drag out 1cc of contaminated acetone from your soaking dish on the surface of the coin. (This is overstated as 1cc is about 20 drops of acetone - more likely the drag out is less than a few drops).
If you then put the coin plus the 1cc of contaminated acetone in the first pure rinse of 100 cc of acetone, the contaminants are diluted to 1cc in 100 cc or a 1% concentration (again overstated). If you now dip in a second pure rinse of 100 cc, the 1% concentration is further diluted by a factor of 100 to 0.01%. You can argue the assumptions, but a double dip reduces contamination by a factor of at least 1000.
The same can be done with distilled water if you are unsure of the purity of the acetone. Dip in the questionable acetone, then double dip in distilled water. Since acetone and water are miscible (dissolve perfectly in each other), any contamination will be reduced by a factor of 1000. Of course, drying a coin with water on it is harder than with acetone as pointed out in previous comments.
If you really are paranoid about your super rare coins, there is nothing to stop you from a triple rinse. Doing that reduces contamination by a factor of 100,000.
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Just a point of notice. OP never mentions rarity on any scale in original post.
Those of you saying that you should dry coins on a microfiber cloth, be aware that almost all microfiber is made of synthetic materials that acetone can dissolve. When you lay a coin on a microfiber cloth that contains materials that can be dissolved by acetone, those materials are dissolving and are being deposited on the coin.
How about ethanol? Is that OK to use ethanol?
I’m afraid of those microfiber cloths with acetone too, that’s why I use 100% cotton white t-shirts and white cotton gloves. Probably some microfiber cloths are cotton, I don’t know, I never checked their labels. Can’t go wrong with white cotton. But then again, I don’t use fabric softener….
Mr_Spud
Go to eBay and get some wooden tweezers and a small wash bottle or 2 [see pic]. Hold the coin with tweezers over your GLASS dish that you soaked your coin in. Rinse with acetone using the wash bottle. Hold the coin in air via the tweezers for about 15 seconds and it should be dry. It will have a measure of moisture on it because the rapid evaporation of the acetone cools the coin surface enough for moisture to condense on it.
If no glass dish is available you can cut the bottom off of an empty square plastic bottle that rubbing alcohol comes in. I believe that the plastic [H or LDPE] has an anti-static additive in it. Gunpowder grains didn't tend to stick to it.
A little water in acetone is no biggie. Unless one has access to spectrphotometric grade or better solvents there is always concern about the quality of the product in cans at WalMart or Lowe's etc. It is transported by tank truck or rail car and when unloaded there is no assurance about the cleanliness of the transfer lines or packaging stations. Best to test it using a mirror or adding some to water to see if it turns cloudy.
Really it does not have to be that complicated IMHO. I use Walmart acetone all the time with no problems encountered regarding purity.
First: what issue with the coin is being addressed? If it is organic residue then organic solvents such as acetone or rubbing alcohol are worth a try.
If the coin has an oxidation issue, and especially copper nickel, silver or gold (or alloys of said) then avenues such as the mentioned will not suffice. Please note that the above Ike dollar example looks to be oxidized to a yellowish color that may not be redeemable if that is the issue of concern. I usually will throw a variety of measures at the coin, but sometimes CuNi are a problem once they have been dipped in Jewel Luster (which is generally a no-no) or similar since the surface takes on a "hard" oxidation that is difficult to approach and I tend to leave alone. But I would try ammonia with no coloring or scents (yuck), and some other methods that can be discussed later....
Second: if it is an organic residue or questionable then I rinse liberally with TABLE water, then massage mild dish detergent into the surface WITH MY FINGERS (yes!), then rinse under the same water for a long time, then tamp (NOT RUB) dry with an high nap CLEAN white cotton towel.
Then I will set coin in acetone but only for a few minutes, and then take a loose cotton Q-tip (make sure the fiber is not tightly wound on the tip), soak it and then tamp the surface. Horror of horrors, and if moderation can be understood, will gently work the surface with very mild swipes that are not with force and not hamfisted.
Then I repeat the steps at the top of this paragraph. There are no problems with residue.
Third: if less than desirable results will then go to MS 70. I will also then go to the rinse, soap, rinse method with towel tamping just described. There are also other solvents that can be resorted to and the coin treated with the before and after methods described.
Other avenues for oxidation can be discussed if anyone wants to.
Well, just Love coins, period.
Thank you.
If you have less expensive coins or a lot to clean some of these methods cited are inappropriate. They are slow and highly costly. Such care might be indicated on extremely valuable coins but not one or two dollar coins. And not in quantities. Much more efficient and speedy methods are sufficient and preferable. You can get pretty good results even when cutting every corner and the failures can still be dumped in circulation or poundage. A lot of the failures are still going to be failures no matter how careful you are. If a failure is otherwise a valuable coin you can still send it in.
Just remember not to be experimenting on valuable coins and avoid mechanical cleaning because it shows up pretty fast. As long as the coin doesn't looked cleaned it's fine. Rinse lather repeat and then rinse and rinse. Pat dry.
MS-70 is a good product for many coins.
As an aside instead of cotton gloves you can get "food" gloves from eBay or Sam's Club among other places. They work great for handling coins, food, peeling onions, picking up after pets or applying things like Voltaren gel that should only go to the places needed and not on your fingers. I also sometimes use them when handling firearms or reloading components. They can be somewhat fragile/flimsy so take that for what it's worth.
When handling coins do it over a mat, carpeted floor or other soft surface that won't damage your coins.
I agree with MS70 with modern mint set coins that get a haze. I always acetone them (in a 1 gallon paint can half full) after a wash but I can do hundreds of coins this way. I had heard that MS70 IS NOT approved by PCGS. It works great though on Clad mint set coins.
My method dip for a few seconds then rinse off thoroughly with water. Pat dry with small smooth dish towel,
When one’s loved one passes on is one way. I could rattle off a few more ways but I like this one.
It's just acetone, it isn't gonna burn your skin lol.*
*Don't hold me liable if it does.
"It's like God, Family, Country, except Sticker, Plastic, Coin."
He certainly called them "super rare" later. Not an actual rarity scale, but...
I meant that more tongue in cheek.
I'm still trying to think of a "super rare" copper nickel coin
..
Acetone will not burn your skin. It can dehydrate it a bit. Some (rare) people can have an allergic reaction.
1913 Liberty nickel.
Worry is the interest you pay on a debt you may not owe.
"Paper money eventually returns to its intrinsic value---zero."----Voltaire
"Everything you say should be true, but not everything true should be said."----Voltaire
Thanks, I sometimes have a problem keeping my tongue in my cheek.
Maybe the OP will enlighten us and I know you just can't hardly wait for that.
see, I did it again
LOL. Yes, I guess that is true. I don't usually hear people refer to nickels as having "copper-nickel" composition.
Nickels are actually mostly copper (75%) with only enough nickel (25%) to give it a silvery color.
Worry is the interest you pay on a debt you may not owe.
"Paper money eventually returns to its intrinsic value---zero."----Voltaire
"Everything you say should be true, but not everything true should be said."----Voltaire
Nickels are actually mostly copper (75%) with only enough nickel (25%) to give it a silvery color.
Didn't know that. Canadian nickels prior to 1981, excluding some war years, were 100% nickel. I thought the same for us up to 64.
There you go educating people again.
Now if the OP would have just left the toned coins in the PCGS slabs, not cracked them out and threw out the labels to shiney up the value.
I know. But I think most people think of clad coinage when you use the term.