Charcoal and wood chips
It is a light, brittle, black substance left over from the half-burning of wood or other plant organs, most of whose compounds have been converted to carbon. This crude carbon is made up of 85 to 98% carbon.
Chopped wood chips or wood chips are one of the quality carbon reducers for silicon production. Wood chips must be free of dirt, bark, nails, sand, wire and other impurities.