I have used Viper Brite, formerly known as Carbonex, to clean aluminum coils, truck rims, and basically anything aluminum.
It is cheap and potent. Handle with care.
They claim minor surface etching and I must agree, does a great job like no other. I used it quite a few times.
I wouldn't recommend it for regular cleaning...just the tough jobs. Will make an old set of junk rims, get mistaken for new, with 2 or 3 washes.
Spray it on, let it foam up (feel the heat), and thoroughly rinse off.
Cleans fucked up aluminum better than every other, and many products, I've used.
It'll burn your skin on contact from mist. So treat it as it is.
Probably available at most refrigeration suppliers.
http://www.refrigtech.com/Product/Coil_Cleaners/Viper_Brite/viperbrite.html