Depends from the flora in the region. Once lived in a city district with trees producing sticky syrup (maple?) and yellow powder (birch?). This mixture was pene

Depends from the flora in the region. Once lived in a city district with trees producing sticky syrup (maple?) and yellow powder (birch?). This mixture was penetrating every aperture in e.g. a car. Went to car wash, the next day car was sticky again. Spruce and pine pollen result in a moss-like layer on the roof quite quickly.