Scott Wade is an American artist who started to create works of art in the dust on the back of car wind shields. I've included a video at the bottom of this post so that you can hear him talk about it and watch him create a piece from beginning to end.
What I like about this artist's choice to use dirt is that it is a temporary medium, meant only to exist until it is washed away. He is not very precious about his art! When we allow ourselves to be "un-precious" about what we are making, different doors open to us creatively. It is a very positive exercise to try out, it can shake loose some old habits and make art-making a lively experience again.
Scott Wade doesn't seem to use this as an exercise though, this is his medium of choice and he's going for it. He shows his art all over the place and has really found his niche. You can see more about him here: http://www.dirtycarart.com.
"Scott continually seeks opportunities to bring Dirty Car Art to the world, making appearances at fair, festivals, and corporate events, and contributing his talents to ad and PR campaigns the world over." - http://www.dirtycarart.com/
Another way to simulate a reductive technique like this is to use scratch board where you are scratching away the black surface to reveal the white beneath of to cover a piece of paper in charcoal and then remove with erasers.