I agree with soaking but I have soaked for a day or two just to really try and let oil work its magic. Steel wool will work, but copper or bronze wool is preferred. The steel wool can supposedly get into the pores or something and cause more rust later. I haven't seen that problem before, but it sounds plausible enough that I found some copper wool. My personal trick was to soak in penetrating oil for as long as I could stand to wait and then use a nice thick oil for gently scrubbing.