I have a North facing upper and lower roof.After I had the the trees trimed back I noticed a large area of green on both roof shingles.I have asked my local Home Depot if they had anything to remove this, and they looked at me like I had two heads.I tried spraying a 10% bleach solution on it but that didn't work.I was also affraid I would bleach out the color of the shingles.Any ideas?
Steve G