Cossie: notice the "hehehe". What are you going to do, lock your car up in a garage and not use it? It's *only* a car (even if it IS a benz)...

The way I see it: those brushes look like they turn pretty slow. I would think that the cars and trucks in front of you at any given time are hucking more-damaging debris at you. Plus, because you have eyes you can visibly tell if your car has been sandblasted. You'll notice 1) a lack of paint and 2) that gleaming metal look.

And unless you live in New Jersey, Florida or some other environmentally-unfriendly place I'd doubt that they'd spray anything toxic or non-bio-degradable on the city's streets and parking lots. I would think that would cause thousands of lawsuits to occur (if you find that they DO in fact use harsh chemicals call me - I'd gladly lick a "clean" street to make a few mil in damages).

Then again, I'm from California. To help your paranoia: think of your car as 'disposable' and know that every mile you drive is one mile closer to your car's death. Feel better?