Just noticed outside that I have black smoke coming out of my exhaust. I have an M55 FS. Also smells a little. It vents vertically at 90 degrees. I clean once a week and just emptied out the bottom of my T. There's wasn't much in there. I'm burning Spruce Pointe and just started with some barefoots. The siding is getting black from the wind blowing. 2nd year burning. Never happened before. Any thoughts?