Guerilla windshield art by Scott Wade 

Remember the last time you couldn’t resist scrawling “WASH ME” on a grimy car windshield? That same impulse is strong in these reverse grafitti artists, who use the city’s grit and pollution as their main materials, and actually wash it off to create art rather than spraying on a new layer. Check out these photos and this video clip of a team in action.
Alexandre Orion‘s work in Sao Paolo, Brazil. 

“Moose,” aka Paul Curtis works in San Francisco