Spoke with the dealer and was told that 90% of the fogging problems were due to deposits on the outside of the lens, i.e., hardwater stains. I tried a plastic cleaner called Novus #1. It did indeed clean most of the fogging except for some areas that had light etching, similar to what a dishwasher does to glass, but not as severe. Will try Novus #2, a mild abrasive made to polish off the etching. Once I have polished off the hazing, I will regularly use Novus #1 or another plastic cleaner preservative called Plexus. Apparently, these products are regularly used by motorcyclists on their windshields.