Can paint thinner damage rare coins?

chrisVAM54

I have a 1902o proof Morgan dollar in MS63 that I treated with paint thinner just in case the coin had any PVC on it. When I look more closely at the coin it now appears to have some small, fine scratches on it. Could the paint thinner have caused this or perhaps were these scratches already on the coin and I didn't notice them? I rinsed off the paint thinner with filtered tap water and then rinsed it off again with distilled water. When I dried off the coin I didn't rub it but gently patted it or gently layed it down in a tee-shirt.

Unknown

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Insider2

Curious, where did you hear about this conservation method? Did you grade it MS-63?

What you have done is either hairline the coin yourself OR more probably, removed the "skin" and exposed the impaired surface.

MS-63 Proofs generally are impaired in some way so it may still be a 63.

PS In my experience, paint thinner cannot ruin a coin.

Goldbully

Welcome to the forums, @chrisVAM54

1630Boston

Welcome , ask questions, especially before you dip rare coins in anything
Also.................have fun

10000lakes

@chrisVAM54 welcome to the forum.

If the coin has an O mint mark then you have a proof like business strike, not an actual proof.
The fine scratches could be die polish lines.
Do they look like this?

1630Boston

@10000lakes
Nice informative info and pics, thanks

astrorat

Yes ... depending on purity.

Paint thinner is a generic term for petroleum-based distillates with unknown purity. I would not recommend using on coins.

Xylene may or may not, I have no experience with metals. I can't recommend one way or the other.

Acetone is safe, IF it's pure. If you use the hardware store acetone, you run the risk of introducing impurities.

However, none of these chemicals will cause scratches to the surface of the coin, that is either done during the "conservation" process or the solvents removed substances so that the scratches were revealed. Unless the "scratches" are die polish lines as mentioned above.

JBK

You are braver than I am….

Paint thinner to me is a harsh chemical used for cleaning paint off things. I don’t know its actual chemical makeup, but regardless I would only use pure Acetone (I have never used it but that recommendation is based on what I have read here). Some paint thinners I have used are a bit oily, and they seem like they may leave residue. The problem is, any residue they leave may not be washed off by water as they are presumably petroleum based and you would need a degreaser for a thorough cleaning.

Also, filtering tap water may or may not remove all the things that can cause issues for a coin (sulphur, for example, or salts). I would be worried that certain chemicals in tap water might cause issues the minute they hit the surface. Distilled water should be OK (but won’t remove oils).

Lastly, if you have a proof it is not MS63, but would be PR63….

Otherwise, it sounds like you handled the coin so as to avoid hairlines, so like other have said, you may have just revealed the surface that was there all along…. It sounds like a nice coin.

Insider2

Unfortunately, the miracle chemical acetone works too slowly in some applications and a different chemical (like paint thinner) keeps a production line going.

I made the same mistake and overlooked the "o" after the date.

ricko

@chrisVAM54... Welcome aboard.... As stated above, paint thinner will not cause scratches on a coin...It likely removed what was concealing the scratches. I would not recommend paint thinner for cleaning coins... residues can cause future problems. Stick with pure acetone to remove organics. You should redip your coin in acetone now to remove any residue from the thinner... let it soak for a few hours, then redip in clean acetone and rinse with alcohol. Cheers, RickO

topstuf

You can't buy acetone or cool guns in California.

logger7

Harsh chemicals in there like gasoline which I would never use on coins.

BillJones

I would not want paint thinner anywhere near my coins, but that's just me. I only use stuff when necessary, and I usually avoid the "when necessary" coins in the first place. As a dealer sometimes you end up with them and have to do same work. A gold piece that had been glued into the book comes to mind. I was able to get the stuff off with acetone and got the coin certified

messydesk

Since "paint thinner" usually refers to a petroleum-based product, it's unlikely to be effectively rinsed with water. As mentioned by others stick to acetone. Do you have a picture of the coin in question?

Insider2

@messydesk said: "Since "paint thinner" usually refers to a petroleum-based product, it's unlikely to be effectively rinsed with water. As mentioned by others stick to acetone."

Not picking on this poster specifically as most agree with this. All I'll repeat is that paint thinner, turpentine, naphtha, gasoline, etc does not hurt coins. Products such as these (not gas - LOL) are often used to quickly prepare the surface of a coin for conservation when acetone (often the first step) has no effect on the residue.

There is a lot of "commonly accepted knowledge (?)" in numismatics. I suggest posters try some different products before offering an opinion.

morgandollar1878

Welcome to the forum. Paint thinner should not hurt coins. The morgan that you are referring to if it has an "O" mint mark on the reverse is not a proof. It could have proof-like surfaces though. If you are seeing hair line scratches it is probably due to the coin being lightly cleaned or circulated. Hopefully you did not wipe the coin off after you treated it as that also could have caused the scratches too. Pictures would would get a better assessment of what is going on.

RogerB

Yes. It could also damage common coins. It is not a reagent grade product.