It is a problem all too familiar to proud car owners. A Sunday afternoon washing their beloved motor, only to wake up on Monday morning and find it has been used as a target by the local bird population.
Bird droppings are not only unsightly, they contain some of the most corrosive ingredients nature has to offer. Around the world, efforts are under way to develop coatings for the car's steel bodywork which will not only resist the harmful effects of bird droppings, but also shrug them off.
Now an unlikely weapon is being used by the German chemical company BASF: synthetic pigeon droppings that can help test super-tough car paintwork. Harvesting bird poo is no one's idea of fun, so the BASF team has found a way to mimic the effects using ingredients extracted from pig pancreas preserved in tins.
The pancreas secretes corrosive digestive enzymes - protease, lipase and amylase - which can all be found in bird droppings. When Ursula Huesmann, a BASF chemical engineer, removes the enzymes from the can and waters them down, the mixture looks and smells as revolting as the real thing.
Bird excrement is not the only torture that car paintwork endures - chips and scratches add insult to injury. Dr Michael Golek, from the BASF coatings plant in Münster, explains how, depending on your speed, "small stones or grit may turn into projectiles that can reach several hundred kilometres per hour".