Chimney coating is a process that involves the application of a protective material to the inside of a chimney. This helps to prevent the buildup of SOOT and FLUE, which can cause blockages and other problems. SOOT is a black or dark gray powdery or flaky substance made up of tiny particles of carbon that is produced when something is burned. FLUE is an enclosed passageway for smoke and other gases to escape from a fireplace or furnace.