I just finished cleaning my chimney with a new brush I used. It is an 8 inch nylon bristle brush with very flexible bristles. These are often used in applications where flexibility is needed, but I found it did a much better job on a straight pipe than my Rutland poly brush which has much heavier and wider spaced bristles. Anyway, I noticed that the sheet metal at the connection points inside of each of the pipe sections has a spot or spots that are not flush with the inside of the pipe. I think this was caused in the past by the heavier bristle brush when it caught the edge. I am not really sure. I was just wondering if this could ever be a problem with the pipe. I doubt the flue gasses would be forced into places they shouldn't go (since there are plenty of seams in the pipe that are not completely sealed), but I figured I would ask anyway.
