What's the secret to cleaning IP lenses without scratching them? It never fails...I get a new car and after a few weeks the IP lens gets dusty or dirty and I get the urge to clean it. It seems that no matter how soft of a MF towel I use, I wind up with scratches. Is there a method that is preferable to wiping? Maybe a soft brush? I have yet to touch the lens on my 2011 Outback until I receive some professional advice...please help, the suspense (and dust) is killing me 
