I've noticed a couple of sizeable defects on my windshield recently that all appear to be inside the glass. One looks like an etching and the other looks like a huge smudge. Unfortunately, both are in areas that are very distracting when driving in direct sun. Can anyone shed some light on the windshield design that has these looking like they are inside the glass? Nothing I've used to clean or polish has made a dent on either spot.