Alum. cleaning

["Edward Hamilton" <hamilton@ptd.net>]

I've spent too much time cleaning and polishing a pair of side-draft Webers
and a Cannon inlet manifold.  There are "spots" on the Aluminum or in other
words, the Aluminum is not even in color.
Is there some cleaner or chemical dip that I can use to even out the color?
Anyone else experience this problem?

Thanks in advance,
Ed Hamilton