Cleaning green stains from asphalt roof shingles?
Is there a "right way" to clean green stains from asphalt roofing shingles on the north side of my house? I am assuming that the stains are some sort of mildew, not moss, since they appear to be just a flat stain (not fuzzy like moss). The stains are on a porch roof and are visible from the second floor windows, so I'd like to remove them. My first thought is to use some sort of bleach solution, then rinse it off, but I wasn't sure if it would be harmful to the shingles. Is there some other better/preferred method? Your thoughts are greatly appreciated. Thanks.