This might be old news and a repost. If So... sorry. I found a website featuring an artist who draws some really cool stuff on dirty cars. I wrote a short article on my website about it if you want to read more. Too bad I can't hand draw that well. I would be leaving some sick looking messages on friends' cars. haha http://www.509media.com/news/dirty-car-artwork/ I attached a pic here as well.