Creosote is a carbon-based particulate that is carried up the chimney in the smoke given off by a fire. It is left behind when condensation occurs as a result of heated vapors making contact with the cooler brick or metal flue. Their formation occurs in three stages and creosotes are combustible in all of them. Stage 1 : The first stage of creosote formation is a fine powder that can easily be swept out of the chimney with a brush long enough to reach the entire flue. The easiest type of creosote to deal with, stage one creosotes can cause slow-burning chimney fires which often go undetected by the homeowner. Creosote in this stage is soot, made up of carbon particles and ash. Stage 2: In its second stage, creosote takes the form of crunchy rock-like deposits and is more difficult to remove, requiring stiff brushes and scrapers. Creosote is porous in this stage and may at first be flaky, puffy bubbles of unburned carbon that can be broken up and scraped off. Stage 3:...