If you use a chemical rust remover, you will have to refinish - and refinishing over pitting gives a very second rate result. As Claven2 suggested go after the rust with a sharp brass scraper. You can also rub with a round object - this tends to break and crumble rust. If you leave brass residue behind, use bore cleaner. Keep the surface wet with a fine oil. Kroil is good. Clear active rust, and you can often wind up with a not unpleasant patina effect. If used with skill, a very fine, well broken in, wire wheel can do wonders. The face of the wheel is NOT used - rather the side, with a scrubbing effect. This isn't the sort of wheel you buy at Canadian Tire.