My tiny stove is making little pieces of slag. I am mostly burning (Brown?) Ash. And some cardboard, junk mail, etc. The slag isn't plastic--i put it in the flame of a propane stove for a while.
The top (cream) is a heavy cotton canvas. The sides and bottom (blue) are nylon canvas, with a sealing layer. I put a piece of felt on the foam, under the cotton.
Cut the mattress into 3 pieces: two will be the couch, and the third will be used in the reading nook. All three will be used as a bed. I also got some perfect fabric to upholster it with.