Black Sugar

Black sugar is a form of crystalline precipitate or a particulate pollution by-product unique from creosote caused by the burning of low grade coal in the 1940–1960s. The outgas from burning coal would be a by-product for the heating of family housing. Black sugar was often found on porches and the cold ductwork and caused the high carbon, soot-loaded gas to precipitate on the floors and walls and... (Wikipedia)