only heat the the peroxide in a throw away type dish -- leave the coins out till you bring it out of the microwave --then put them in -- by the way any metal item and microwaves don't mix -- figger you know this but I've found that it never hurts to remind folks of that fact --- Ivan
Peroxide can make silver coins turn dull or grey colored. Careful! I only use peroxide with dug coppers. For dug nickels, I use salt and white vinegar. For silvers, hard running water and a gentle brushing with a camel's hair brush--that is, IF these coins are dug.