Ok furthering the rear window washer idea. I can't recall the last time I've used mine. Heck, I'm still on the factory fill of washer fluid at 21,000 miles. But... I think it could be easy enough to fabricate a small piece of sheet metal that would be held in by the rear hatch that would deflect the washer fluid up and back behind you instead of at the windshield. Use it for those times when you would like for people to get off your back. Then you could get creative with what you put in the resivor. I don't think trying to clear your window while driving is illegal.