Autoglym researchers studied the process and determined exactly how the damage is caused.
In direct sunlight and in warm conditions, paint lacquer heats up, softens and expands. At the same time, heat bakes the droppings onto the surface, making them hard and crusted.
When the paint lacquer later cools and contracts, it moulds to the uneven under-surface of the hardened deposit.
The result is an imperfect, textured paint surface that appears dulled compared with the unaffected paint.
Tests showed the degree of damage caused was not related to the acidity or alkalinity of the deposit, but rather the ‘grain-to-liquid’ content. The grainier the droppings, the greater the distortion in the paint when it hardens and moulds around it.
Autoglym said waxes and polishes that combat chemical wear – such as acid rain and UV sun damage – would provide limited protection from bird droppings, although they were likely to make it easier to remove.
The car care product manufacturer said the longer the deposits remained on the paint, the harder they were to remove and the more damage they were likely to cause.
Here is Autoglym’s advice for removing bird droppings from cars:
- Remove the deposit at the earliest opportunity
- Motorists should use a moist cloth to gently lift the deposit from the surface
- If the deposit is dry or doesn't lift easily, place a moist cloth over it for ten minutes to soften the deposit
- Dispose of any cloth or wipe used to remove bird droppings immediately and carefully wash your hands as bird lime can harbour diseases