Just wanted to see what others firebox are looking like after a burn. I have been burning 16-20 MC splits and have a shiny black tar like substance along the back and coming around the corners to the front. There may be a rogue split above 20 MC but not more then 25. Everything above that is a nice tan/brown color. I have been burning shoulder burns over the weekends when air temp is forecast to the low 30's. Been burning some pine and cherry wood. Once the wood is nice and charred I lower the air in stages down until I'm at 1/8 air open for my long over night burn with the cat engaged.