I use LPS, it can be sprayed directly on live computer boards so it should be safe. Most well stocked hardware, electronics stores, and auto supply houses carry it. I spray a little on a q-tip and wipe the contacts with the q-tip. It might cloud the mirror if you got some on it so be careful. Some lenses are worse than others for oxidation on the contacts. I have a Tamron that is really bad about oxidation. Too bad, but it is my favorite carry lens so I just re-clean every few months and live with it.
I was wondering about that grease that you get for treating the contacts on light sockets, circuit boards, etc? Anyone brave enough to try it?
Papa Smurf says that life is uncertain, eat dessert first!