Sanding works on lightly pitted stainless.
Here's a repost on the subject from long ago:
I have polished up a number of really beat up SS Smiths.
For jobs like these, you will need a lot more than Mother's.
I use auto body sandpaper (dry - tried it both ways) cut into 1" wide strips.
Depending on how bad it is, have started out with as coarse as 320 grit.
Different areas will probably need different grits to start. You may even need to use a fine file to smooth out deep gouges, usually the bottom of the triggerguard where the gun has been dropped.
Strip the gun, re-install the sideplate with all flathead screws. I keep a set of screws just for this purpose.
For the flat areas, I wrap the sandpaper around a little aluminum sanding black I made.
After all has been worked with the first sandpaper, go to the next finer grade. Work it with this one to smooth out all the scratches from the last grade.
Repeat this with finer and finer sandpaper until you end up with 2000 grit.
You will quickly learn that if you don't completely remove the previous scratches before going finer that you will have to back up and do it over, Trust me on this!
After its polished to 2000 all over, start in with Mother's and rub, rub, rub. I start out polishing with a cotton shop rag and end up with a microfiber cloth.

Here are some of the worst that I have done:

This model 67 was a complete junker. $150 at the LGS. Dirtiest and most beat one I ever saw. Soaked 3 days in Ed's red before even starting on it:


This one had a very coarse sandblast finish with lots of pitting (yes, stainless DOES rust!) like it had been a boat gun. It took more work than the others:


This was another well-used gun dinged all over and rusted in a couple spots:


And one that looked as if it had been dragged behind a truck:

Final note: Unless you REALLY know what you're doing, do not use any power tools!

__________________
-jwk-
US Army '72-'95