Birds seem to regard human transportation vehicles as ideal spots in which to dump their waste. In fact, there’s some indication that red cars are more likely to be the recipient of bird deposits than other colors, possibly owing to their color being more eye-catching. But regardless of your make and model, bird poop—the white splatter of excrement that so often crashes right onto the roof and hood of your car—is more than just unsightly. It can actually damage your vehicle’s paint finish.

The problem with bird droppings is that they’re a hybrid of poop and urine. Birds eliminate waste through their all-purpose intestinal and reproductive organ known as the cloaca, mixing feces and urine with high acidity and then letting the concoction fly. When a bird drops its payload on the surface of your vehicle and is allowed to remain there, it will begin to burn through the clear coat, wax, and paint, eventually making an etching as deep as a piece of notebook paper. The bird has essentially left a corrosive material on the car.

Worse, a warm day will expedite the damage. That’s because the sun will cause paint to expand, making it more susceptible to the poop’s acidic profile. If the conditions are just right, bird poop can leave a permanent mark in minutes.

The best solution is, of course, prevention. Keeping your car in a garage or under a car cover is ideal. You can also get a wax coat, which will delay the bird poop from reaching the paint and allow you time to clean it up.

If birds have already landed a direct strike, cleaning your car promptly with detailing spray and a microfiber cloth is one of the best ways to address the problem. (Avoid sponges and towels, though, which can be too abrasive for a car’s finish.) A garden hose works, too. Some people advocate for WD-40, but as that can damage wax, it probably shouldn’t be your first choice.

When bird poop winds up on your car’s windshield, don’t use the windshield wipers, as they can move around debris found in the droppings and potentially scratch the glass. Follow the same steps above to remove the droppings.

For bird poop that has been left to linger and caused etching, it can be tricky—though not impossible—to address. Superficial etching can often be resolved by sanding the surrounding paint to match the divot. Deeper etching may require the services of an auto detailer.

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