Before I reseasoned it, I baked the cast iron frying pan for over four hours in my over, starting high and lowering the temp as I went. Followed instructions from a cast iron collectors association.
Then I reseasoned it and baked it again, but not quite as long. It is really fine and cooks great with no change in flavor. What I had thought was rough iron was actually burned on stuff, and it all came off.
It was a drastic move, I know, and I won't ever do it again, or will need to do it again. It actually originally belonged to my uncle's grandfather, and then given to my father and then me. I told my kids, after I am gone if they don't want it, to give it to my cousin's children. They suggested I just buy something new, like a set of LeCreuset cookware!! Shows you what they know.