Not sure how small your small parts are, sounds like some of these suggestions are for jewelry, but the smallest of my small parts are nuts and bolts. Grab them with the pliers and wire brush them. It's the cleanest way, environmentally friendly and fast.
Example, all of the parts for the parking brake in the picture, from the pad down to the cables took a little over an hour to clean up. When their done they look like they did when they were manufactured, still have sharp edges and original-tooling marks from dies, etc.
Here’s are more examples of "small parts" that were all wire brushed on a pedestal grinder, no sandpaper, no sandblasting, no chemicals. Parts were brushed, prepped with Dupont 3900S Fast Clean and sprayed with Rustolium. Every thing in black, except the axle beam, that was wire brushed with a hand tool:
http://rides.webshots.com/photo/2136558830098611668rwjgca http://rides.webshots.com/photo/2421733140098611668UuEbDZ (Big)
http://rides.webshots.com/photo/2770730910098611668EJJKmH (Big)
Denny Graham
Sandwich, IL
