Creosote is a black tar-like substance caused by condensation of gases in smoke and more likely a result of burning wet wood; it can build up over time under certain circumstances and can be dangerous as it becomes a fire hazard. It can be almost impossible to remove with conventional fireplace cleaning methods.
Different products that are fairly easy to use have been developed to deal with creosote buildup.
One application is a creosote remover spray that is applied into the firebox before a fire is burned. It can be used on a regular basis to prevent creosote buildup. Another product is a creosote cleaning powder that is applied to areas of buildup that crystallize the creosote for removal. This second process has 5 steps, including 1) applying and activating the powder creosote cleaner, 2) preparing the area for cleaning, 3) removing the large crystallized creosote deposits, 4) then treating the underlying layer of creosote deposits, and 5) final removal of creosote deposits and cleanup.
These creosote removal (and management) products are usually available at local fireplace sales and service retailers. These products can be applied by the fireplace user who should be reminded to follow manufacturer instructions including utilizing personal protective equipment such as safety glasses and particle masks. This type of maintenance by fireplace users is not a substitute for regular chimney cleaning and checking.