I noticed last night as I was burning some garbage that cardboard seems to burn a lot slower than it used to. I wasn't burning regular boxes, but boxes that products came in, like wine, cereal, and coke.
These boxes, cause of whatever coating they are putting on them, or whatever in the hell they put in them now, burn real slow. And I even threw them on top of a hot fire. Makes me wonder what is coming out of them in that smoke...