CSL Creosote Sweeping Log - Chimney Cleaning Reduce Removes Treats Dangerous Creosote Treats Fireplaces Woodstoves. A simple, effective, and nontoxic solution for cleaning your chimney, while enjoying your fireplace. Creosote Sweeping Log (CSL) burns like a standard fireplace log, while simultaneously helping reduce dangerous creosote buildup. Great for fireplaces and woodstoves! Tested by Omni Laboratories. UL Approved. - Brown Helps maintain your chimney while you enjoy your fireplace Reduces the weight, thickness and flammability of creosote For woodstoves and fireplace inserts Use every 60 fires! Burns up to two hours.