Try a small painters steel wire brush attached to a pole. I’ve been sealing 20 years and have yet to find anything that takes moss off so quick. Scrape as much of the large stuff off as you can with a shovel, then set your blower air exhaust next to where your scraping and go to town. Nice thing with this method is it requires no water or extra eqipment and you can carry it with the rest of your equipment- just watch your hands near the steel wires, they are sharp.
