I understand some coloring of the glass is normal on a pellet stove, but how much would indicate a problem? When looking at the glass on the door, there are two small \ / sections in the lower corners where the glass is getting brownish, especially when run on low (and since this winter is bizarrely warm yet, we're running it on low more often than not). I'm pretty good at keeping her clean, however not the the point of climbing to the top of the chimney with the leaf blower. Sounds fascinating, but if God meant me to be hovering 35+ feet up in the air I would have wings, not feet. LOL