Originally Posted by
unworthy1
actually it's the chemical reaction of the oxalic acid in those polishes (and Mothers is just one of many brands that contain OA) that produces the black residue on the rag. If there are abrasives in the polish, too, it's those that "remove aluminum"...most of these polishes (Super7, Happich Simichrome, MAAS, Autosol, etc., etc.) make a big effort to point out that they are NON-abrasive.
Thanks for that....dang, can't seem to go a day around here with learning
something 
But, if you're going from a satin like finish, say after 0000 steel wool, to a mirror finish scratches are being removed, be it chemically or abrasively right? The black is still aluminum or some other compound of aluminum I'd imagine? (I absoluetly SUCKED at chemistry
).
Regardless, OP made the part like or better than new...and that's the schweet part!
Reminds me, I got a tall Nitto Technomic stem with like a 140mm reach out of a junk box at an LBS (it was $4, couldn't leave it...) that I'm going to polish up and put on the "pay it forward" thread. The only cost? The story of why you have a frame for which you need an extra tall stem with a 140mm reach. Should be interesting