I would use a softer brush first like a nylon bristle, before using a metal brush. If using a metal brush, use a brass brush first before using a harder steel brush. You really just want to take off the surface rust. Most of the time it can be wiped off with a rag and WD-40.
There is a spray rust inhibitor and lubricant made by GM/AC Delco a while back. I used to use it on rusted bolts, and after a day or so the rust was gone and the bolts look brand new. I have a part number somewhere around here.
Machines: Gamma 6004 2-point w/ Wise 2086 & Babolat Sensor Dual