When it's time to knock some old paint off small parts, often those with a bit of rust pitting or scratches, I have had good luck using either an electric drill or a die grinder in conjunction with wheels of ScotchBrite or brass.
Holding a hand drill and working over a small part can get tiresome, not to mention sometimes dangerous. The die grinder is smaller, as are the wheels, therefor a lot easier to maneuver.
Using padded jaws, I gently clamp a 3/8" drill in a secure vise. Don't get too carried away with the vise handle. If you hear the drill's case crack, simply back off a half turn. A trigger lock allows both hands on the part. With a reversible drill, it's easy to turn the wheel in a downward rotation that throws debris away from your face and helps prevent the pad from "grabbing" the work piece.
For the die grinder, I usually clamp the work piece in the vise as a matter of safety.
Use eye and hearing protection... the die grinder and compressor can do some hearing damage. I've also plucked a small brass bristle from my chin! Stuck there when the wheel started shedding pieces. I avoid using gloves with rotating tools. Learned experiences can occasionally be scary.
There's also a bench grinder behind this messy photo. A buffing wheel makes aluminum shine. I usually clean the alloy parts after polishing then shoot the part with a coat of clear lacquer. Works well for parts that don't get a lot of handling.
I always prime steel bits with a rust-preventing primer before color top coating.
