Devinetly get any other coins you have out of those coin sleeves. As Rob says it looks like it is made out of PVC which reacts with coins and damages them over time. If you are lucky and get to them quick enough the acetone might help. You can buy acetone on ebay. I always make sure i have a bottle handy. Try and get 100% acetone. I've tried verdicare as well but it didnt really work for me. Maybe the coin I used it on was too far gone.