You can also get you a plastic trash bag. Coat the pan generously with Easy Off oven cleaner and place in the trash bag. Seal it tight and let it sit over night. Carry that rascal outside and hose it off (might sound obvious but you do not want to splash yourself during the process). You should be down to the bare metal at that point. Then follow steps listed above for reseasoning. I usually give them a quick wipe down with oil and place in the oven as it is still cooling down before I store the pans away. As long as you have removed the moisture from rinsing it out and given it an oil barrier before storing it should not rust back on you. I pick up old pans from time to time at flea markets and yard sales. Whenever I stumble across a keeper in bad shape I use the bag method. You can also place in a self cleaning oven but heck I just dont like the extra clean up of the oven when all the crud falls off.
If it can't be smoked .... try frying it. It that don't work, it's probably best just left alone