you could use a brillo pad which will slighty scuff the surface, then polish it up with yir autoglym metal polish.
#00 wire wool will get rid of the pitting and only dull the finish slightly.
Then as above, AG metal polish to finish it off.
Above method is perfect for the finish on the exhaust tailpipes.
.... what i am polishing is a caterham superseven bonnet, so cant use alot of pressure which is why it's bad to clean.
cheers guys.
whats pitted ali?
Try having a look thro this thread. Could help you.
http://www.detailingworld.co.uk/forum/showthread.php?t=11754&highlight=aluminium+rolls+royce
fantastic.... good find, thanks for that mate.
The other thing to remember apart from bi-metallic corrosion is that aluminium does oxidise and will turn a dull whitesh colour over time. So either polish it from time to time or get it coated in a less reactive material.