Most worn Bakelite cannot be polished once the shiny outer layer is worn through. Underneath is the wood flour/phenolic resin mix, and it won't take a shine.
I used a clear enamel on my RCA Whirlpool agitator and it came out pretty good (except for the runs). I know others have had good results with clear enamel as well.
Haven't tried to run the machine as yet with the refinished agitator, though.