These fire logs contain Rutland SAFE-T-FLUE, a propriety chimney cleaner that modifies soot and creosote deposits in chimney as they form. Normally these deposits are flammable sticky, tar- like substances, however, these fire logs or used once a month in the fire, changes the creosote into a powdery, loose non-adhering deposit which is easily brushed away. The use of flue-renew TM fire logs or any chemical creosote remover does not eliminate the need for regular professional chimney cleaning. For best results, and maximum safety, we recommend a professional chimney cleaning, and then following a vigorous cost-effective preventive maintenance program using flue-new fire logs to combat creosote build up between professional cleanings. Most effective in airtight stoves and inserts. Easy-to use Individually wrapped logs are added to the hot embers of a wood fire.