Cars not, they go to wash. Those who don't are indeed visibly dusty/moldy. Wet roofs and other surfaces -- pretty much all the time, especially in humid climat

Cars not, they go to wash. Those who don't are indeed visibly dusty/moldy. Wet roofs and other surfaces -- pretty much all the time, especially in humid climates (like Hong Kong, where the research is made). Same for glass windows (we have window-washer job for that reason). Surfaces can be cleaned with pressure washer, but unlike purely aesthetical reasons, I'm saying that the main feature of this material may stop working in a matter of days due to even minuscule amount of growth.