henryphull.com/blog

Some are calling the technique “green advertising”, some others call it “enviromentally friendly” and it is also being called “reverse graffiti”.

The idea, as good ideas are most or the time (I will never cease to repeat this!) is very, very simple: the ads are imprinted in street walls, roads, pavements or any other dirty surface by… cleaning it. 

Two companies in Europe are already offering the service and companies like Puma, Smart and ING have been already advertising this way.

They are pretty long lasting if no one decides to clean the whole wall, and as GreenGraffiti states, “the more GreenGraffiti™ the better”… because they are cleaning the streets not making them more dirty!

via Ugly Doggy