Living by the coast does have its downsides. I reckon a seagull will let loose a good 500ml of guano in one squeeze! I was driving along a while back and I honestly thought someone had lobbed a stone onto my roof. Pulled over to find a massive seagull poo-strike that was drying rapidly in the sun. Used a jetwash to remove the offending mess but yes agree, rubbing is the worst possible thing.
2012 F30 328i Lux', 8SAT, Melbourne Red