Felt polishing tips, preferably conical. Rouge is the equivalent of automotive rubbing compound (say 10000 grit), a very very fine abrasive. Buy one with the flex shaft. Sam's club had the Deluxe kit for less than I paid for my middle of the road model. Also has a drill press attachment in the kit. Flex shaf gives more control of the tip, IMO.
600, 1000, and 2000 grit sandpaper work nice also, but a Dremel has so many uses that you'll be glad you bought one. Never use the grinding tips on a gun. If you buy stones for polishing, buy them from a tool and die store or Brownell's, as hard arkansas stones are too coarse for gunsmithing for most purposes.