Some companies use it as a form of green/clean advertising, such as BBC, Microsoft, Starbucks, Sony and Green Works (a company that sells plant based cleaners). Others use it as a way to spread environmental awareness, such as Moose (also known as Paul Curtis, a street artist from the United Kingdom and one of the first artists to use this technique), and Alexandre Orion (a Brazilian street artist). Personally, I've been finding these green ads and ideas really innovative and insightful, and this one really strikes me because its foundation is sustainable and it's more focused on spreading awareness rather than just advertising.
Unlike the green billboard post I made earlier this month, this form of green advertising has met some legal backlash. However, since this art does not involve applying paints as it only consists of cleaning surfaces, and since no permanent damage is created as a result, the creators can't necessarily be prosecuted. Below are some featured works with links. More information on The Reverse Graffiti Project collaboration between Green Works and Moose can be found here; and more works from Moose and Alexandre Orion can be found here and here.