I've just bought some Russian copper coins on eBay, but I found that one of them has PVC residue (or something similar) . How can you remove this without damaging the coin? I had some egyptian alluminium coins from the 50s with similar problems, and I used acetone, which seemed to be very effective..but I'm guessing that copper is going to need something else. J.
The acetone will remove it, but it maqy also change the color of the coins now or down the road. You could use any number of other solvents to do the same thing, but all of them will react with the metal. But if you don't do it - the PVC will definitely eat away the metal. Damned if ya do and damned if ya don't.
