I'd like to refinish the insides of a couple of old water kettles. Both have chipped enamel, one has a leak because of it and the other one has this brown paint-like mystery stuff stuck to the bottom. I was thinking about putting a coat of paint or something on the insides, but I can't fathom what might work. I would, you know, like to be able to boil water in these puppies once I fix these problems. I can't throw them away, they're just too freaking beautiful... I don't know what to do, any suggestions?