Acetone (Pure) - When Do You Use It To Clean Coins

If you have any just junk circulated silver coins you could practice with those. Just let them soak for 10 - 20 minutes depending on their original condition, and I don't know about copper? Seems like I read somewhere about acetone reacting with copper and light? So maybe practice in a dark room with just a plain penny to see what happens?

I use acetone on any coin since it doesn't react with any of the coining metals.
It's great for removing crud on coins (glue, dirt, etc.)
It will not remove toning.

I have a Half Cent that I soaked for several months.
No problems.

Yes.


Acetone removes "organic goo" - things like stickytape residue, paint, ink, oil, varnish, wax, or the green goo that can accumulate on coins stored in the wrong type of plastic coin album page. Acetone does absolutely nothing to metal or metal oxides or other corrosion byproducts, so it won't affect genuine toning or patina. It might remove a "fake patina" if the fake patina is organic-based (ie painted or glued on). Nor will it do anything to help remove bronze disease or other unwanted corrosion.


Diluting the acetone will only reduce its effectiveness.


If the "goo" doesn't start to come off within a minute or two, it probably isn't going to come off with acetone at all. The only reason to soak coins for prolonged periods is to minimize the amount of rubbing or scrubbing needed. Soaking it for weeks or months will not hurt, but won't help much either. As others noted above, try to use only metal, glass or ceramic containers to hold the acetone, as it can depolymerize some plastics (such as polystyrene) with dramatic effect. If you must use plastic containers, test the plastic first.

It always helps to use several acetone baths in series. Acetone dries quickly, and if there's "goo" already dissolved in the acetone, it will re-deposit back onto the coin if allowed to dry there. Also, try to minimize the amount of contact your fingers or other body parts have with the acetone, as it can suck the oil and sweat right out of your pores and re-deposit that onto your coins as well. For handling acetone for prolonged periods, nitrile gloves are recommended.

Final safety notes: treat acetone as if it were petrol/gasoline. Keep out of reach of children, no smoking or flames, and use in a well-ventilated area as some people can have an adverse reaction to the fumes.