My first corn cob, a missouri meerschaum legend, seemed to me to change colors as I smoked it. I couldn't tell if I was imagining it or not. I picked up a small, almost pure white made in china corn cob that is the only thing available around here to smoke cherry captain black in and after ~5 bowls, there are dark brown dots that I'm pretty sure weren't there when I got it. I smoked another bowl as I typed this and more showed up, so I suppose that answers my question. Now, if I could find a way to fix the bottom with the texture and durability of styrofoam, this would be perfect.