I have used the Dremel buffing wheels a number of times on inlays and other small objects.
For anything larger than an inlay, I use my bench grinder with a cloth buffing wheel.
I have not tried the Dremel compounds but I have tried Dico brand Emery, Tripoli, Stainless, Plastic, and Chrome Rouge.
These (and the bench grinder size buffing wheels) are carried by my local Ace Hardware Store.
My opnions of them on brass, German Silver, steel and stainless steel are:
Emery: Dirty, removes material slowly, doesn't polish well.
Tripoli: Marginal for material removal, marginal for polishing.
Stainless: The BEST thing sence sliced bread. It will remove material if used aggressivly but if used lightly it polishes all of the above metals to a mirror finish. This is the one to get.
Plastic: Works well on 1978 GMC tail light lenses. Not much else.
Chrome Rouge: Very disappointed with this. It is VERY SLOOOW to do anything.
These compounds come in tubes which are about 1 inch in diameter and 5 inches long.
To use with your Dremel, just touch the spinning wheel to the compound and then to the part. Don't overload the wheel. It doesn't take a lot to do the job and too much compound will just schemer on the part and stop the polishing action.
With the proper use, the Stainless will polish the sear nose and tumbler full cock surface to a mirror finish.
For more of my BS on polishing follow this link:
METAL POLISHING
Towards the bottom of the following link is a drawing of how to polish the Sear and Tumbler without making them dangerous.
POLISHING SEARS AND TUMBLERS