Question: With great effort I removed the scaling finding much of the enamel eatten away by years of use. Once the scaling and rust is removed, is the pot safe for use?

If the kettle is iron under the enamel (you will know- it rusts) it is safe to boil water in. If it is mystery metal, it is NOT safe. If you truly love it, you could probably take it to one of those (expensive, hard to find) folks who replace the tin lining in copper pots and find out about relining it, but you might do better to plant a miniature rose in it and get yourself a good electric kettle...