I just restored the finish on mine and it had gotten pretty rusty. I sprayed it with WD-40, then I hith the rust and old seasoning with 50 grit sandpaper. After I got the rust off, some of the old seasoning refused to come off, so I washed the WD 40 off and "cooked" it on my gas grill on high temp for about a half hour. All of the old seasoning turn to ash and was easy to was off. After this I buffed it with #1 and #0 steel wool and 110 grit sandpaper. After all was said and done the pan looked like a new pan in the gray. I then seasoned the pan as normal. It was a pain in the butt , but it was better than tossing it out.
Scott.