I use the Mother's aluminum polish and then follow that up with Mother's Billet polish for a mirror finish. I use a detail spray to clean the black hardened aluminum polish off of the wheel between applications. I then seal the metal with a product from Wizards products, that is called "Power Seal"
http://www.wizardsproducts.com/store...8-oz-p-15.html.
I have found that it works quite well in keeping the polished parts clean of water spots.