I've got a couple of Ike proofs that look like they have crud on them (they're in cardboard 2x2's). I was thinking about hitting them with an acetone soak, but I wondered if hardware-store acetone is good enough, or if people prefer a higher grade. I have 91% isopropanol on hand as well. Unfortunately I no longer work in a science lab, so more exotic stuff isn't convenient to hand...
Unless one is proficient in metallurgy , I would strongly urge one to NOT try this with any piece of a valued collection.
More than likely, if it is a whitish film or spots that it is beginning toning and obscures the mirror finishes. Acetone will no help that. If it is more greenish, then it might be pvc film from earlier storage days, and if so, acetone can remove that, but there may be damage beneath. Acetone on silver is non-reactive if pure acetone like hardware stores sell, but final rinsing has to be done on a vertically held coin with fresh acetone and held that way until dry. On silver proofs, the mirror is so delicate a surface, that any chemical reaction can damage it. Dipping in a thio-acid dip like EZest -could- improve it, but it also could do the opposite.
I agree with desertgem, acetone will not help with any hazing or film spots. There are other "dips" that you can quickly dip it in that will remove it. I won't mention the name, but you can get it any hardware store. I dont want to get yelled at! edit: As to your original question though, proper acetone can be purchased at the hardware store. Its when people use dilluted (with other chemicals) acetone, like nail polish remover for example, where it becomes a problem.
I would be very leerly of trying to clean proofs. I might try it but would certainly practice on junky ones first.
These are already junky, really; I bought them for silver value, and I think they're officially "impaired". They do have nice mirror fields, it's just that there's stuff on them. I'll try to get pictures later this evening. I'm tempted to put this off indefinitely, but with silver's reactivity, I'm concerned that damage could be accumulating.
