Ya got me started! Here's the scoop, There are basically two steps to resilvering a mirror. The first is cleaning all the old silver off the back, Thoroughly ! Using paint remover and nitric acid. Then applying the new silver. I noted that Rustoleum and Krylon make "Rust effect" silver (With or without silver?) paints. Anyway, I searched yahoo, resilvering mirrors! Also, they make and sell kits to do this but they aren't cheap.
Terry