I've been burning nothing but some Elm lately. In the past I've noticed little klinkers or what look like very hard ash. Very similar to coal klinkers. Lately with the exclusive use of Elm There is much more. Elm burns with very little ash, so I've had to clean the stove out a lot less often. Today it went out, so I cleaned it out with the vacuum. The two center fire bricks were fused together with a large klinker. When I removed them and broke the klinker, it had become a part of the brick so much that when I broke it, the brick actually came apart. Anyone ever hear of this? Now I need two more bricks. Where can I get them?