Reverse graffiti: street art with a green twist?

I meant to write about this some time ago when I stumbled across this post from Le geek c’est chic. Ciara notes that GreenGraffiti uses reverse graffiti to serve advertisements — while maintaining a carbon neutral footprint.

“With the help of a template and a high pressure water sprayer an advertising message is cleaned out of the dirt,” says GreenGraffiti, “[t]he result is a high impact message and a cleaner street.”

While the Dutch agency focuses on corporate messaging, variations on reverse graffiti are many. Environmental Graffiti has this post detailing 35 such works. Of note is Alexandre Orion’s Skulls in Sao Paolo: