in most cases the wheels are just clearcoated with paint. scuff em and shoot em. id reccomend a grey scuff pad and some soapy warm water. after you do that hose em off real good. wipe them down with some waz and grease remover (and paint store will have it in a spray can even... go there for the scuff pads too) and then paint them.
Wax and grease remover- get the can and a couple paper towels. spray it on the part you are gonna clean. wipe it around with the paper towels. WHILE ITS STILL WET - dry it off with the OTHER set of paper towels. all this stuff does is bring the crap to the surface, you gotta wipe it off while its wet. repeat for the other wheels then paint.
2009 Ranger Sport - 4.0L/Auto 3.55 Limited slip. Black. 2500K Nokya fogs, Vanish cover, PreKey Leveling kit and 4 cupholders!
1994 Mustang GT - 5spd
1969 Mercury Cougar -in progress 428 swap! Guessing low 12s?