(h/t: Neatorama for finding this)
Ever heard of reverse graffiti?
A number of street artists around the world have taken to expressing themselves through an innovative practice known as Reverse Graffiti. Taking a cue from the “Wash Me” messages scrawled on the back of delivery trucks, they seek out soot covered surfaces and inscribe them with images, tags, and even advertising slogans using scrub brushes, scrapers and pressure hoses.
Now that is a contemporary urban art form rich with theological implications.