Folks,

Before replacing any glass, I would definitely recommend trying any of the usually available "glass stripper" products. Usually, you apply these with lots of elbow grease, then rinse it off with a hose, and then repeat and repeat and repeat until NO water sticks to the glass anymore. Once you get there, then you've truly got nothing "on" your glass mucking it up.

Head to your favorite auto parts store, spend five bucks, and then an afternoon really putting some work into it. If you still have a problem after that, I sure think you can call it a "certified" problem!