Bird droppings and your paint

Why they mark the paint

Bird droppings contain uric acid, and many also carry grit: seeds, bits of shell, or sand from gulls that feed in parking lots. The acid attacks the clear coat, and the grit scratches it if you wipe carelessly.

Heat is what turns a nuisance into a lasting mark. On a sunny day the paint gets hot enough that the clear coat softens and expands slightly. As it cools in the evening, it tightens around the dried dropping, and the outline can stay pressed into the surface. That is why a dropping left over one hot weekend in July can leave a dull imprint that a dropping in April would not.

Removing a fresh one

The aim is to soften it and lift it off, not scrub it.

• Wet it well with water or a quick detailer spray. A wet microfibre towel laid on top works too.
• Wait a minute or two so it softens all the way through.
• Pinch and lift it off with the towel instead of wiping across the paint.
• Fold the towel to a clean side and gently wipe what remains.
• Rinse or wash the area afterwards so no residue is left drying on it.

If it has already dried

Give it more time. Lay a soaked towel over it for five minutes, rewet it, and repeat until it comes away easily. Do not pick at it with a fingernail, an ice scraper or a credit card, and do not use paper towel, which is rougher than it seems.

Once it is off, you may see a faint dull ring where it was. Look at it in sunlight from a low angle. If it disappears when wet but shows again when dry, the clear coat has been lightly etched.

When a mark stays

Light etching can usually be polished out, either by hand with a fine polish or by a detailer with a machine. Deeper marks, where the clear coat has cracked or lifted, may need more work. If you are not comfortable polishing, ask a detailer to look before you try, because heavy polishing in one spot can remove more clear coat than you want.

A touchless wash will often take off fresh droppings if you get to one within a day or so, especially on a car with a protectant layer. It will not remove an etch that has already formed.

Keeping them off the car

Where you park makes a large difference. Light poles, power lines and the edges of big-box parking lots attract birds, and so do trees with berries. Spots near the Thames and around open fields get gulls and geese. If you have a choice, park in open space away from all of them.

Keep a small kit in the car through spring and summer: a bottle of water or quick detailer and a clean microfibre towel in a zip bag. With that, dealing with a fresh dropping takes about a minute in the parking lot instead of waiting for the next wash.