I cleaned my chimney, I do top down with a brush and the pipe is straight from the stove up. On my Encore if you sweep the sweepings fall straight down on and behind the bypass damper and can also fall off to the sides and clog the chamber. I used a cardboard template and made a shield from a piece of aluminum coil (aluminum used to be bent to cover fascia) to fit over the bypass damper. The coil is thin and flexible so I made it with flaps that once in place I can bend outward and protect the chamber. It worked great, swept down and it caught it all so I could vacum it out easily. In the past If I didn't place something over the damper it would go behind it and down into the chambers.