Has anyone else pondered the problem of the rear view monitor lens often being dirty and blurry? The back of the car seems to get covered with dirt especially during rainy wet driving. I have to often wipe off the lens with my finger. Then I realized that constantly rubbing the lens could scratch it and make it permanently blurry. So it's best to clean it with some clean water and a microfiber cloth just as we do with our eye glasses. There is not much info about this lens in the Owner's Manual and perhaps they assume everyone knows how to clean it? I believe it is a polycarbonate lens but it may be glass too. Either way they both are susceptible to scratches when rubbed with the wrong things.