Hi Sunrise!
C.W. gives good advice. It isn't a great idea to introduce tiny metal fragments to a magnetic assembly.
Others on this Forum introduced me to Evapo-Rust, a liquid non-caustic surface rust remover. If you can't (or won't) remove the drive wheels you can always soak paper towel with Evapo-Rust and wrap the rusty part of the wheels with the soggy paper for a few hours. Over night would be better. Then finish the job with a Dremel tool using a Scotch-Brite (non-metallic) abbraisive Dremel head. If you want the rims to shine, polish them with some Mothers Mag polish. If your rust is pitted rather than surface rust, realize that you have lost part of your surface. You still go through the same exercise to get what's left of the surface as conductive and smooth as possible.
BTW, when using a Dremel, expect small particulate matter to be broadcast in the air. So wear a disposable safety mask so you don't breathe it in. The same may be said of safety goggles. I know it isn't macho, but it is smart.
