Here's the deal. Posted this many times and I promise it works. Get some "Blue Magic" aluminum wheel polish from an auto part's store. I get mine from Kragen. Follow the directions, basically wash and dry. Apply the Blue Magic and rub until a black film apears. Now before you wipe clean, sprinkle a bunch of Corn Starch or Flour on the wheels. Yep, the same things you can make cookies out of. Now, wipe clean and check the difference. The corn starch works better but flour will work as well. I've been using this on my Weld's for about 5 years and it really helps. You could also apply a coat of car wax after to prolong the intervals between polishings. You buy aluminum wheels for a reason...don't give up and paint them! This process is very easy. If they are really bad do it a couple of times and you will get a better shine each time.
