I have been working on shining up the parts on my new machine. What's working for me is the dremel and the little brushes you can buy. I know it sounds scary, but start with a small area, underneath to build confidence, lol.
I start with the "silver wheel" brush, make sure you are using the edge and are always moving in the same direction (learned that the hard way). I then use the "gold" brush, last the nylon (black) one. Next, I take some aluminum polishing compound and work my way from corse to fine.
I wouldn't do this on plated areas, only all metal parts that are rusty and pitted. This method will remove plating, which of course will leave you with an exposed surface. I'll post some pics when I'm done so you can see how it works. It won't remove all the pits and scratches (unless you start with a coarser brush), but it will give you a nice polish and shine!