[VAC] Polishing Aluminum Tanks

[Rik & Susan Beeson <rik@xxxxxxxxxx>]

I just picked up a 5 gallon (20 pound) aluminum propane tank at a
nautical swap meet. It has obviously been used on a boat -- the surface
feels smooth, but looks mottled. And there was some slight corrosion
under a label that I removed from the tank. My question is -- can I
wet-sand the tank (with maybe 400 paper) prior to polishing it, or will
that scratch it so badly that it can't be polished? If sanding isn't the
way to start, what is? Acid wash? I was talking to the folks at Iowa
Boys in N. Hollywood the other day, and they said they start every
trailer polish job with an acid wash. But I've heard others say that is
a bad idea.

I solicit your opinions!

Thanks very much,

Rik