When I polish gun parts, here's what I do.
Put a piece of 400 grit wet/dry sandpaper on a piece of flat glass. Squirt some glass cleaner on the paper to get it wet. Work the flat parts of what you are polishing back & forth & in a circle to start with. 400 cuts fast, so only use it to smooth & flatten the part.
Then switch to 600, then 800. work your way to 1500. You'll learn quickly how long to stay with each grit of paper. Rembember to keep the paper wet & squirt it often to clean the paper.
Then, with a Dremel & a cotton buffing wheel of the correct size & shape, buff the part to a mirror finish. You can use any type of metal polish. I like the liquid or paste kind. Use some heavy cut to start with,& work your way to the fine stuff.
Finish up with some polish to get that mirror finish yor looking for.
I use Mothers chrome wheel polish to finish off with.
Keep in mind that you don't want to remove too much metal, just enough to flatten & remove the machine markings from the part.
Oh, by the way. I use a boot box lid on edge when I run the Dremel to keep the polish from flinging all over the bench, walls, tools ect. Place the part inside & polish away. Wear an apron to protect your clothing.
