Corncob for use as charcoal

Although corncob, which primarily consists of cellulose, hemicellulose, and lignin, is not toxic to people and can be digested, the outside is rough and nearly inedible in its raw state, and the foamy part which is completely bland when mature is most likely to be unappealing to most people.

Because corncobs burn particularly well as a source of heat, they have been used for millennia to roast meat on a spit, barbecue, and heat bread ovens. 

It was highly regarded in the past for producing long-lasting embers that were also used to make ember irons.