well i know this isn't a lawn question, but when the grass stops growing i know everyone looks for ways of making more money. i have a customer that asked me about cleaning her roof. usually i clean the leaves off the roof and clean the gutters, but this time she asked about cleaning the shingles to remove the stains and discoloration. has anybody ever done this and if so what is the best way to clean them? some suggestions have been to pressure wash or to use a 50/50 mix of bleach and water but, i was afraid the bleach would kill the grass and bushes where it runs off the roof. has anybody tried these methods? any information would be greatly appreciated.