What a great feeling to get up on the roof and do it myself, scrubbing to my hearts delight for as long as I want so I know it is as clean as it can be. My first two years burning I paid a service to do it, $100 the first time and $125 the next and they weren't even up there for more than five minutes. Ouch! After that I bought a used brush and three extension poles from a local shop for $40. Much better now!