First-rate product_ cleaned my chimney (metal liner) in about 30 minutes and saved $200. But the _anual that was included was absolutely worthless (clearly written by a non-native speaker, who is pretty dumb). Fortunately I have a friend who is an ex-chimney sweep and he gave me some tips: 1) work from the inside/bottom and shove the brush up to the top until it hits the cap; 2) work slowly down the chimney reversing the drill_ direction before you move on; 3) dove your shop vac hose into the chimney along with the drill (and have a good filter/bag); 4) when you get to the end, go easy on the speed because it gets unstable/crazy. Do this and it_ a piece of cake. When I finished I got on my roof and sang Step in Time.?