Green
I polished a few things on my Freedom Arms Revolver (Loading Gate, Ejector Rod Housing, Ejector Rod Knob). What I did was get one of Dermel's Polishing Kits. These contain a couple polishing "stones" (different "fineness" (grit)) and rouge.
Don't know if this was the way to do it but taking my time I was able to achieve mirror finishes on those items without changing their shape/contours. You may want to pick one of these kits up to do your polishing.
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Schmit, GySgt, USMC(Ret)
NRA Life, Lodge 1201-UOSSS
"Si vis Pacem Para Bellum"