You could try Brasso, available in home-improvement and discount stores, in the cleaning section. It's a metal polish. it's actually a very light abrasive that might help mask scratches. however, if the aluminium is coated with something (i do not know), this could cause some discoloration. even if it doesn't, it takes many many repeat applications to show any results.
you might look into jewelers paste, which can be used to polish glass, metal, stone. same thing as above, but much stronger...
pnw