The problem with Ed's Red is that the primary solvent is acetone, which will evaporate too quickly. Soaking with WD-40 (or similar) is probably a good start, just give it time to work, and maybe use a toothbrush to scrub the parts. Heating with a hot air gun won't hurt the parts, or you could try one of those small pin-point flame burners, that will concentrate the heat into one area without being able to overheat parts.