The rims on my Cuda were really oxidized from sitting outside in the driveway for many years. I did it the hard way with lots of elbow grease by wetsanding. I started out with 800 grit paper, then moved to 1200, then 1500, and then finally 1800 or 2000 (I think, don't quote me for exact numbers, I did this a little of 2 years ago). I started out with wheels that looked like this:
And about 40 hours later (seriously), they looked like this:
Oh I forgot to mention that I polished them after wetsanding. I guess I should have been more specific.