[John Brown]

For years I've been cleaning aluminum intakes and transmissions with scotchbrite and bathroom tub and tile cleaners that contain weak phosphoric acid. I think aluma-prep does too. Just did a net search on phosphoric/nitric dip and came up with information on "electropolishing". Do the search on electropolishing, then call someone in your area that does anodizing. They may have some of the answers you're looking for.