If you are a gun collector more than likely you've seen rust on atleast one of your guns. An old gun smith showed me this trick when I was young. Get a nickel (the older the better), gun oil (I prefer Hoppes 9), and cleaning patches. Use only a nickel because the edge is wider than any other coin and because it's smooth without rough ridges. Rub the rust spot with oil and leave it damp. Get the nickel, slowly and gently rotate it's flat edge on the rust spot. Wipe the spot clean with a patch. Then repeat the process over and over until the rust is gone. Works great. Many people I've told this trick to wouldn't try it because they thought it would scratch off the finish on their guns, that is until I showed them how well it works. If you do it right the finish stays right on. If you don't believe me please try it for yourself.