Just as "moss graffiti" is leaving the home-decor crowd and beginning to hit the streets bigtime, street artist Strook (Stefaan de Croock) is doing the reverse moss graffiti. His tool is 'water' as he uses a high-pressure cleaner to spray away the moss, leaving large landscapes of space invaders on walls.
To make moss graffiti is fairly easy (be sure to clean the blender crazy clean after this). You'll need to gather one or two chunks (fist size) of moss. Mix this with 2 cups of buttermilk (or acidofilus / kefir style yogurt), two cups of beer (low alco is fine) and 1/2 tsp of sugar. Rip the moss into small "crumbs" and but in the blender with the yogurt, beer and sugar. Blend until evenly goeey. If you feel this mixture is too runny, as if it might drip when painted on a wall, add corn syrup until you reach the right consistency.
Now paint this on a wall (stone, concrete, etc) pick one that doesn't have to suffer direct sunlight at all hours. Spray your finished art with water and if you can, return to the moss-graffiti to re-spray it once a day for a week to encourage moss growth. You can cover terracotta pots in your garden with this, benches, chandeliers. And street art your way to fame all over town, of course. Question is, how long until an entire ad campaign is based on moss graffiti, or the removing of moss? I give it five minutes.