Paul "Moose" Curtis is considered the pioneer of reverse graffiti art, also known as clean tagging. Graffiti usually gets a bad rap, because it's associated with vandalism or property damage. Reverse graffiti spins that on its head by doing the exact opposite.
Perhaps the most popular example of graffiti art is the dusty car with the words "clean me" written with a finger on the windshield. Clean taggers like Moose use natural cleaners to wipe away the dirt and grime on public surfaces to create elaborate drawings/murals.
Moose recently tagged San Francisco's Broadway tunnel. We showed a few seconds of his behind-the-scenes video on today's episode. Here's the full-length version:
Moose went with a "green/nature" theme for his Broadway tunnel project. As you can see from some of Dennis Yang's photos below (his Flickr), the amount of detail is really amazing. I hope he visits LA soon.