Lots and lots of passes with Mother's Aluminum and Mag Polish then I like to hit it with White Diamond at the end. Occasionally I will hit the rim (or whatever I am polishing) with some 2000 grit Wet sandpaper, but usually it's just more polishing.
I've taken some Scheeren wheels that looked really bad and made them shine like chrome. I did spend a number of hours and a lot of elbow grease on them.