Enameled cast iron. From what i can see, once upon a time someone re-coated this tub with enamel, to make it pretty. now, its chipping badly, I can pick away small chunks in the bottom of the tub with my fingernail, and see the previous coat of discolored yet solid looking enamel, or whatever that white coat is. It isn't really acceptable as is. I know there's a dude in my town who'll re-enamel a tub but this is out of my budget. a new tub is also not an option.

should I: a) sand, heat-gun, or chemically remove what I can, so it won't chip more while people bathe? the sides and rim of the tub look like they've got a good bond happening, problem is exclusively in the bottom of the tub. b) learn how to re-enamel it? or c) --???-