I use a few different methods depending on what type of part it is and how shiney i want it.. No matter what it is, it is going to take time and plenty of patience. I have quite a collection of small polishing tools and a bench top polisher with quite an assortment of compounds (rouge) and different sizes and types of wheels. Most commonly you would be polishing aluminum if you are talking about cases, carbs, rims etc. I usually do a few stages before the actual "polishing" cleaning, sanding, sanding again, then another cleaning before buffing/polishing.. small parts need small tools and of course larger parts need bigger tools.. Here is a good link for info and things you may need... http://www.caswellplating.com/buffman.htm
I highly recommend a decent dust mask.... when polishing you are actually sanding things down and the particles are very very small. Trust me you don't want to breath this crap in...
Same here. Not only the aluminum dust or whatever metal you are polishing, but some of the compounds have something in them that "according to the state of California may cause cancer"