Bird droppings don't corrode paint

New research from Britain says bird droppings are not the corrosive danger that people have long feared, although droppings are still associated with damage to paintwork.

Autoglym, a leading car care company, says the damage actually comes when paintwork warms and then cools and moulds to the uneven texture of the hardened guano.

"As paint lacquer warms - in the direct summer sunshine for example - it softens and expands. At the same time, that heat dries and hardens any bird droppings on the surface," says Autoglym.

"As the paint lacquer cools, overnight for example, it contracts, hardens and moulds around the texture of the bird dropping. To the naked eye, this moulding at a microscopic level appears as dulled or etched paintwork. The light's reflection is interrupted by the imperfect surface, unlike the undamaged paint surrounding it which gives a clearer reflection."

Autoglym worked hard to understand the effect of poop, using strongly acidic, neutral and strongly alkali bird dropping 'substitutes' in long-term trials. It found the biggest differences in damage when researchers varied the grain-to-liquid content, as a grainier texture caused greater light distortion and dullness when the paint moulded around it.

Autoglym says the best defence is to remove any poop as soon as possible, as even wax and polish treatments that protect against chemical attack from acid raid and UV sun damage provide limited protection from the paint moulding to bird droppings, although they will make them easier to remove.

To minimise the effect of bird droppings on your car's bodywork:

1. Remove the deposit as soon as possible.
2. Use a moist cloth to gently lift the deposit.
3. If the poop is dry or doesn't lift easily, place a moist cloth over it for ten minutes to soften the deposit
4. Immediately dispose of any cloth or wipe as bird lime can harbour diseases