I bought badly oxidized douglas red label blaster wheels off of Ebay for $50and set about cleaning them up. The first step was fine grit sand paper to knock down the high spots, some 600 grit to start with on the really rough stuff. Then I went up to 1200 grit sand paper over the whole things.
The next step involved power tools. I started with a 7" hand buffer with a wool buffing pad and No7 rubbing compound. I started with heavy coating and worked the surface to a dull black mess and then wiped off the black stuff and spun the wool over it until it started to work the polishing compound in. Once the black stuff starts to "buff off" the finish really starts to come out and it starts to look polished. The last step is polishing compound if you want to REALLY polish them up to a mirror finish. I was done with rubbing compound because I wanted them shiny but didn't require mirror finish.