When I checked my chimney 2 weeks after using CSL, I could still see black sooty material.Did CSL not work?
Yes it worked. But CSL is designed to remove the dangerous creosote that is the cause of chimney fires. It will not always remove loose dust that often forms further up the chimney. That would require a mechanical cleaning that you should consider doing when it builds up to levels that interfere with the draft of your fireplace.
