Any polishing compound will work, used with a clean rag and some 'elbow grease'. Flitz, Simichrome, Mother's Mag & Wheel Polish, Brasso, etc. will all get the work done on brass or nickel bolsters. The Flitz, Simichrome (it's pink, BTW) and Mother's will also work pretty well for stropping also. In fact, the polishing compounds will also work very well with your Dremel polishing wheel; just be careful not to linger too long in one spot, on Delrin or other plastics on your handle. The speed of the Dremel and the compound will melt Delrin in about two seconds, if you don't keep the wheel moving.
If scratches are still too heavy to remove with the polishing compound, some 2000+ grit wet/dry sandpaper should take care of that. Then follow again with the polishing compound, after sanding. Both brass and nickel will sand easily, so using a higher grit is generally a better way to start. Go lower in grit only if scratches are very deep, or if there are dents or other dings in the metal. Then start down around ~400/600 grit and work back up the grit sequence, through 2000 or higher and follow with the polishing paste.
David