sawdust burner

Very useful when cold weather camping.

Take a large metal barrel/bucket and cut a hole in the bottom.

Cover the hole with a length of PVC pipe long enough to come out of the top and pack in sawdust as tightly as you can.

Slowly pull out the pipe to leave a hole down to the bottom of the barrel

Light from the bottom (using paper is easiest): it will burn up the hole you made and then down, very slowly over the course of the day.