We had a pot of cranberries boil over and carbonize under the cooking pot. In an attempt to clean, I used authorized cleaning agents and finally resorted to the razor blade to get the material off. The surface still felt a bit rough where the carbonized material had been, and upon closer, magnified, inspection found small chips in the glass/ceramic surface. Of interest is the fact that most of the chips were associated with either the small white/gray dots on the surface, or the white/gray circular lines that mark the burner locations and sizes. It appears to me that there is differential expansion between the black glass and the white dots/lines which has caused the chipping, or there is a differential chemical reaction between the glass and white/gray dots or lines and the carbonized material which has caused the pitting. I would appreciate any thoughts you might have based on the above analysis of the chipping. Thanks, Wally Gwynn PhD.