I do - it works great.
I use about two gallons of chlorine, cup of soap, 3oz of TSP -- add 3 gallons of water.
Hit bad spots with pump-up sprayer and spray entire roof with XJet. Let set about twenty minutes and rinse with the XJet.
Sometimes, I don't even get on the roofs. Spray and rinse from the ground.
WORKS GREAT. Chemicals for an average roof: $10.00