Despite people saying cast iron has been restored by fire for hundreds of years. Don't do it! This method will mess up your iron.
When cast iron gets too hot for too long, it will turn it reddish pink. That color can never be removed and it will not hold a seasoning.
If you find cast iron with this look, stay away from it. It has heat damage that cannot be fixed. The oven method can do the same!
Some people will tell you to use a wire wheel or cup brush to clean cast iron. This will also ruin your piece due to making it shiny.
It's easy to see the wire wheel or cup brush cleaned pieces. They hold seasoning with an odd color and bad marks on the piece.
If you find a piece with deep shinny marks with blotchy seasoning pooling up then chances are it's been cleaned with a power tool.