Very good advice already. If the rust is pretty bad, an angle grinder or electric drill with a wire brush makes things go faster. The cloth backed "sandpaper" sold for cleaning copper pipe before soldering works good too.
I just watched a podcast from Cook’s Illustrated on reconditioning cast iron cookware. It was really interesting and helpful. If you don’t have an ipod I believe you can get the same information from their web site www.cooksillustrated.com.
I first used oven cleaner, coated it and placed in a plastic bag for 24 hours, scrubbed with copper pad and or Sos pad, rinsed. Dried it. Then placed it in my oven in the self cleaning cycle. So easy and cleaned it great. Scrub and cleaned with water and dried again. Then seasoned it, a lot of info on Google. I put a small layer of Crisco all over my pan, placed upside down on rack with a sheet pan on lowest rack, then baked at 350 degrees for 2-3 hrs, then wiped dry with a paper towel and cooled. Works great. I reseason with more Crisco over the stove on low for 20-30 mins as needed to keep it from not sticking. Good Luck
TUMBLEWEED wrote: I first used oven cleaner, coated it and placed in a plastic bag for 24 hours, scrubbed with copper pad and or Sos pad, rinsed. Dried it. Then placed it in my oven in the self cleaning cycle.
No need to clean it with oven cleaner first. The oven's self cleaning cycle will burn everything off so there's no need for that extra step.