We have found the best way to remove moss from the roof is by using the back of a push-broom. We flip the broom on its back, the wood side, then walk from top to bottom in a straight line from the ridge to the gutter line. The moss gets knocked off and rolls down into the gutter where we can conveniently collect it before we treat the roof. Any excess that falls off we collect and bag to be thrown out. If the moss is too small to be knocked off by the broom, if its lower than the shingle above it, then we leave it. When we treat the roof with our solution the moss and anything it is feeding on will die off, and over time crumble away. Another way we have found to be useful is just using our hand with a glove to scrape the moss off in highly visible areas. Neither the broom or your hand will void the warranty on your roof. You can certainly use other tools that do not damage your roof, but this is what we have found to be most effective.