Yep, the boys are correct. What you have is a layer of titanium dioxide, inside and out. When titanium is heated above 1620* F, its crystalline structure converts from the alpha to the beta phase. This means nothing to you, of course. Then, when the metal cools back down past 1620* F, it reverts back to the alpha phase. This is when oxygen will be incorporated into the surface of the metal, forming a tenacious layer of titanium dioxide, measuring just a few angstroms thick. This layer refracts light differently, with the color of the patina dictated by the thickness of the titanium dioxide layer. Feel free to scour the pot with an S.O.S. pad--it won't hurt the titanium, and it might possibly shave off a bit of the oxide coating. The layer adheres to the main titanium metal quite well though. But even if some were to chip off, it won't hurt to swallow it--it has FDA approval for use as a food additive. The white letters on an M & M are actually a titanium dioxide paint.
Now, if the pot does have a non-stick surface, toss it. As was mentioned, your mama don't want her baby eating Teflon.