[acidrain]

I have had good luck blasting with medium (not sure of the sieve) glass beads. My cabinet is a small siphon type beadblaster, with about 35lb capacity. The air pressure is regulated to 60psi, and I use a large compressor with in-line filtration. Water and oil contaminants have not been a problem.
I typically blast in a fairly quick back and forth motion at a distance of ~4inches. I blast only aluminum so that the blast medium is not contaminated.
I tried using aluminum oxide, but found the texture much to sharp, and it often left an ugly blotchy pattern in the finish.

For a polished finish, I machine buff with black compound on a Sisal wheel for the cut, then move to brown compound on a spiral sewn cotton wheel for color. I don't take it any further than that, as the ano process has a dulling effect, and polishing to a mirror finish is a waste of time.
Then, to remove the compound, I've found nothing works better than lacquer thinner and a soft brush. The use of clean solvent is critical, and the disposal of old solvent can be a pain. I live in a large city where hazardous wastes can be recycled by homeowners... no questions asked, so that has not been a problem for me (I am thinking of purchacing a recycling still for this purpose).
After lacquer thinner (and rag dry/polish), a quick dunk in SP degeaser removes any residual traces of contaminants, and water break test confirms cleanliness.