Ok, now that someone is asking about metal polishing/buffing ... this is my area of work.
A dremel will work, to a point. The main thing that gets a peice of metal polished is the pressure applied and heat, along with the type of compound and it's abrasiveness.
Do you have a bench grinder? That would actually work better with a buffing wheel and polishing/buffing compound. If you do have one,
Travers has a couple of polishing kits available. Just plug in "polishing compound" into the search tool. Here is a sample of what I did with a set of raw aluminum louvers I bought from RAMTech-RC
The raw is on the left, polished on the right.
If this is a one time thing, I would be willing to polish it for you at work.This polishing work was done on a 3700 RPM buffing machine with a 14 inch, 5 layers of buffing wheel and green cut/polish solid compund. It makes quick work of metal work.
You pay to get it here and I'll polish it for free. I'll take care of senting it back. Lemme know. Otherwise, check out travers since I know you'll get a better result. Dremel's good, but not god enough to really put on a mirror polish.