I just tried a bag of Barefoot, started stove around 7am and turned off around 5pm. The buildup did not show, just a very little smoke film on one side but the glass looks clear and NOT all black like when I used the Green Valley pellets...... The only thing (which I don't know if it is a problem or not) is the forming of some clumps in the burn pot, this happened before with the Eagle Valley pellets as well as with this Barefoot. What I mean by clumps is that I scoope into the burn pot using a kitchen spoon and see this ash forming of some sort, is this normal? Pellets seem to be burning all the way. Any opinion?