Has anyone ever found material resembling clinkers or hard cinders in their woodstove or OWB? Last year I burned primarily elm in my stove. Some of it was red elm that had laid for a couple years in a kind of damp spot in the woods. Is it possible that the wood absorbed some amount of minerals that then recombined to form these rough looking crusty formations in the bottom of my stove? The logs had no bark that would have held mud or anything like that. Just curious if anyone has seen this also.