Don't know how long it's been about, but I've just found Autosol do an Aluminium Polish for untreated Aluminium. (about £4 on ebay with postage)
Seems to work OK and it's best to have the right stuff rather than anything too abrasive. They also do another one for anodised Ali. i.e. car wheels etc.
Remember to wear disposable gloves or you'll end up joining "the black hand gang".



