An alternative method for fully stripping a cast iron pan is to put it in the oven and run a full self-cleaning cycle, removing the pan when it is stilly fairly warm, dusting out any carbon residue, and then immediately seasoning it before it rusts.

Works well in an electric oven, haven’t tried it in a self-cleaning gas oven. Search online for more details, other opinions, videos. Still skeptical? Try it on the ugliest & cheapest thrift store pan you can find as a test.