Why Does Acetone Keep Leaving Behind Stains On A Coin?

Yes, I am beginning to think this is part of the coin, much like the evil milk spots found on some of our silver.

I have no other ideas. That stinks though.

I have never used xylene before. I think I would have to do a lot of research on it before trying it out on this coin. I don't want to risk disfiguring the coin.

Did you try testing your acetone by letting some evaporate on a clear glass dish as suggested earlier? (with and without exposure to your gloves)

I looked up the Pronto Acetone. The Material Data Sheet indicates it is acetone 50-100% weight percentage and Denatonium Benzoate 0-50% weight. So, maybe the spots are the Denatonium Benzoate,

Denatonium benzoate (Bitrex®) has been used in the United States for over 20 years as an alcohol denaturant. In recent years, it has been heavily promoted for inclusion in household products, gardening products, and cosmetics to prevent accidental ingestions by children. It is the most bitter chemical compound known.

I know this is one of the reason you should not use nail polish remover on coins.

I believe industrial acetone found in the hardware stores do not contain Benatonium benzoate.

Just a disclaimer. I got a C in college chemistry.

I just bought the Klean Strip acetone.




I tried that on the Pronto acetone. The bowl that touched the nitrile gloves ended up leaving behind hazy stains. The bowl that did not touch the gloves was clean after the acetone evaporated. I won't be using any type of rubber gloves after this.




Where did you find the data sheet for the Pronto acetone that said it contained Denatonium Benzoate? The back of the Pronto bottle said the only ingredient was pure acetone so I assumed it was safe to use on coins.

Following everyone's advice, this time I used a new acetone brand, Klean Strip. I also stopped using rubber gloves. Just dipping the coin in this new acetone does not get rid of the stains. I still have to use a q-tip wet with acetone to press on the stain. When I pick the coin out of the acetone bowl I use by bare hands but I wear cotton gloves while using the q-tip. The haze/stains are still there but less. So overall, I think the result is better than before. Here is what the coin looks like now:



Also, can someone please tell me if the spot on this picture on the bottom where I circled in red is supposed to be a stain or is it a coin's natural toning? This stain-like spot is on other parts of the coin also but it is only possible to see when you tilt it in a certain way under light. You can't see it on the scanner pictures so I had to use my phone's camera.

Here is an older thread on CCF that I talk about xylene a bit and it's differences and similarities with acetone. xylene is similar and does basically the same thing but it comes with much more health risks.

http://goccf.com/t/398235&whichpage=2#3412791

Something to consider. When using either acetone or xylene please use caution, only use them in a well ventilated area (outdoors is best) never around any type of flame or spark, try to minimize any contact with your skin, and please dispose of the left over solution properly not by tossing it into the street or just pouring it down the drain. We have a great hazardous chemicals disposal, so I put left over into a jar until time to drop it off along with my motor oil waste and roommates multi gallon film developing waste. (I know there is silver in it nut it's not enough for me to worry about). We do this a few times a year, and in our city there is no extra cost to do this, they will even pick up from the street if we set up a time.