I use something called The Intimidator. I had to polish three sets of aluminum semi wheels (18 wheels total) and six fuel tanks this last summer. I used the Mother's Powerballs and it worked like a charm. I also tried using the Mothers Mag & Aluminum polish, but it did not work nearly as fast as this liquid polish. Oh, and I only used about 1 1/2 bottles which I didn't think was too bad.
http://www.theintimidatorpropolish.com/