We have a very nice mural on one of the bridge abutments painted by the children of our local high school. Obviously a lot of hard work. This mural has been cleaned several times of graffiti. Some people can't respect someone else's hard work.

I see a simple cure for graffiti vandals (I refuse to call them artists) and litter bugs. Graffiti vandals would be placed on a crew to clean graffiti in their city. They would spend 2 days a week cleaning graffiti. They would not get off the crew until all know graffiti was eliminated from the city. Many of these vandals know one another so peer pressure could keep the occurrences from happening again.

You could have a similar program for litter bugs.