I agree with Steve, and I've turned and worked with a lot of ivory. With sharp tools, it cuts so smoothly. It's wonderful material to work with. But, you're right, heat isn't good for it. It will make it brittle and lead to cracks, even some that won't materialize until later. And, it can discolor the ivory. So, again, keep your tools sharp. Drilling it with sharp bits is as important as your chisels. I've had it heat up when I drill it more than when I turn it. I tend to back the bits out and give it a rest and try not to heat it up then. I always polish mine when done (before scrimshawing or carving, if I plan to do that) with a white polishing paste. I use a jeweler's polish called fabulustre polishing compound. Cheap, and it makes the ivory spectacularly smooth and glossy. I sometimes put Renaissance Wax on, too. But only if I've scrimshawed piece. Otherwise, the polishing compound is all I use.