Most of the dozen nuts picked up off the trail were pretty far along and bad. One was not bad. I left it in the shell thinking it would burn longer with something to retain the oils from the nut. Success! About five minutes or so of burn time. I think a green nut off the tree would be better as these were all on the down side of their life cycle and were soon to be giving back to the earth. One thing I learned was if it is mushy inside, don't try to light it. Smells terrible.