I started to clean from the bottom up going through a 90 degree clean out tee. I got the first white rod though the tee and attached a black rod and got about3 feet past the tee when the white rod broke about 1/2 inch from the metal coupling. Of course the white rod stayed in the chimney. I was a bit miffed to say the least. I did manage to get the rod out, but what did I do to break the rod? Drill speed too fast? I really don't know.