Q: Not long after we moved into our home, some wise guy threw eggs at our asphalt shingle roof. I went up there and scrubbed with every cleanser I could think of, but all I got was a bad manicure. What should I do about this unsightly mess?
—Carrie, Grand Junction, Colo.
A: Tom Silva replies: Egg residue should come off just fine if you flood the area with water while the egg is still wet. But if it gets a chance to dry, or worse, if it gets baked on by the sun, the job isn't as easy. I'd try soaking the area with water, then spraying it with a nontoxic, biodegradable cleaner such as Simple Green, which was originally formulated to remove protein stains. Let the cleaner soak in for a while as you keep the area moist, then gently scrub the area with a soft-bristle brush. Working with cleaners and water on a roof will make surfaces slippery, however, so be very careful.
When you're done, the color of the roofing may be noticeably different, but there's nothing you can do except wait it out. Maybe it will blend in over time.