Just a quick polishing report. There are artifacts in the scans below - reflection overloaded the scanner, I guess. I had an early version vermiculite-filled pop can stove sitting near the keyboard - made from a Squirt can, for the record, not a Coke can. Scanned it as-is:
Walked back to my metal shop and hit it a quick lick with Mother's Mag and Aluminum polish and a shop rag - about 10 seconds. Big improvement, so I put a linen buffing disk on the Dremel and loaded the disk, hit the can for 20 seconds - here is the scan:
If it was a flat piece, it would be a good mirror. I haven't wiped off any residue; that is the way the buffing left it, so it will clean up a bit more. 6061 and 7075 aluminum that I have polished with Mothers and left lying around are apparently as shiny several months later as when I polished them, FWIW.
I'll give toothpaste a whirl in the next day or so and report results. Don't expect to try to ignite anything - I'm too busy right now during the daytime.