Depends on what type of wheel and compound you use. Only black, brown
and white will take off metal. Red and blue will definately just
polish. There's a good guide to polishing metal at
http://www.caswellplating.com/buffs/buffman.htm. The pdf on that page
has some great info on wheel types, grits and materials. I've tried
buffing plane blades to slicken them up but didn't notice a difference
in use.