First timer here. I have a collection of PNNA Convention Medallions going back to the first medal. Many of them are in the original snap together plastic holders with a thin layer of colored styrofoam. The Medallions are in copper, nickel, and silver. The reverses of some of them are stuck to the foam. Before I attempt to mess with them I want to ask the advise of others on how to recitfy this. The Medallions are all in uncirculated condition. I have thought about Acetone and other solvents., soaking in hot soapy water. One suggestion was to freeze them and the foam may flake off. I do not want to destroy the surface of the reverse. I am afraid of course the breakdown of the foam chemically has already destroyed the pristine surfaces. Hope some one has run into this before and has the answer.
A long (2-7 days) soak in distilled water shouldn't do anything to the medals, but might make them separate from the foam. Always start with the method that is least destructive. Stay away from soap/detergent.
I agree, start with distilled water and then if that doesn't work move on to the acetone. I'm afraid there is a good chance though that the reverses will already be damaged.
Should have said more. No rubbing or touching the surfaces. If there is a lot of foam, the acetone will get nasty really fast. It may take several baths. I used to clean up a lot of stuff like this with mixed results. MS finish always came out better. Proof finish would mostly show stains. From there a select few could handle a quick dip and turn out nice. It's a gamble with each piece.