Well, I brushed the liner today and realized that the chimney crown is crumbling away to nothing. The four corners have already fallen off and it virtually has no over hang any more. It looks like it was made with mortar and some gravel. The exposed areas are very loose and crumbly. Maybe I'm a worry-wart, but am I OK to keep burning for this season? There are probably only two months left. The top plate around the liner is still well sealed and the liner is in the clay flue. I thought maybe it would be better to keep burning since it would keep that area drier and keep snow/rain off of it.