When chimney damage is suspected but you can’t pinpoint the source, use Smoke Pellets for testing. They are easy to light, have a neutral odor, and are encapsulated for easy handling and clean-up...
This 4' Pellet/ Dryer Rod features quality nylon bristles and a guide ball to help revent snagging. It screws on Pellet Rods, is very flexible and has threaded male and female ends.