How about a Mercedes-like test?
Automotive Engineer PLUS - Materials
"Mercedes engineers also assessed the chemical resistance of the innovative clear lacquer using standardised procedures. As part of the testing programme, samples of four different substances – sulphuric acid, pancreatin (simulating bird droppings), tree resin and fully desalinated water – were dripped onto the paint surface in rows and left to work their way in over a period of half an hour and in temperatures of 30° to 75°C. The engineers then assessed from what temperature the paint surfaces began to show signs of lasting damage, with target values pre-calculated for each substance. In this test, the newly developed nano-particle clearcoat fulfilled the same stringent Mercedes quality criteria as conventional paint systems."