Do-it-yourself Chimney sweep. Just burn this log in your fireplace or woodburning stove. Clean your chimney or woodstove the easy way. Professional results the safe and easy way. Reduces creosote and tar. As seen on tv. How it works The chimney sweeping log burns for approximately 90 minutes, during which it heats the tar on your chimney wall to an ideal treatment temperature. The smoke from CSL is charged with minerals, which are deposited onto the creosote over a several hour period. During the next 15 days, the CSL treatment will continue to work and the creosote will gradually become brittle and break away from your chimney walls. The particles will either fall back into your fireplace or be lifted away during your next fire. Any deposits that remain, will be rendered less flammable.