Some folks might remember we had an ongoing issue with the one portion of our glass blacking seemingly no matter what we did last burning season. We are NOT having this issue this year. Now, there are a few things that happened over the off season so I can't say for certain what the problem was. This is what has been done/changed: 1) we replaced the door gasket 2) the sweep who came out to sweep the flue and replace the gasket also found the original installers didn't properly level the stove-it is now level (I really never thought to check this) it was out both side to side and front to back 3) last years CSS wood is now what we're using, currently box elder that was CSS in July and August. We were burning bought "seasoned" wood and ecobricks last season. Could have been one or a combo of the above things, or even an unknown 4th thing contributing to it. all I know is I'm happy to have clean glass finally!!