When you are finished polishing, you need to "seal" the metal to keep stuff like soap and water deposits from building up and sticking to the aluminum. I use a product "Power Seal" from a company called wizards the basically puts a sealing film on the metal.
http://www.wizardsproducts.com/store...ction=0&page=2
There are other companys out there that does that, but this stuff works well for me. I drive my daily driver in all weather conditions. Zoops makes a sealant that works well, but it is quite expensive.
Note: Eagle rims are hard to keep shiney, they are somewhat of a satin finsh rim.