I know this will work on billet aluminum, not so sure on stainless, but wort at least a try (like on the backside of one as a test...):
Using a lubricant of some sort, such as KY warming lotion, mild dish soap, etc, start with 1000-grit, then 1500-grit, and finish up with 2000-grit.
Once you have the surfaces absolutely as smooth as you can get them (run your fingers over them, if you can't feel ANY bumps or ridges), work in a polishing agent. For billet alum, I went to an auto parts store (AutoZone) and picked up Mother's Amazing Billet Aluminum Polish. I'm pretty sure they will offer something to polish up stainless with as well.
For a mre detailed explanation, check out my Untitled Project worklog (still a work in progress, BTW),
HERE, starting from post #10 in the thread
Good luck, and post up some success pictures