I have the exterior plastic flashing on my Hehr windows on my 1970 Scotty and in the Florida heat this summer the plastic on one started to warp and bend out from the corner so I put it on my maintenance list and decided to pull off the plastic flashing and caulk in the corner of the glass a bit where I saw a tiny gap. I also put a small bead around the four areas of the window for good measure. Well, it turned out messier than it should have and thinking I was using clear that went on white then dried clear, well you guessed it, an hour later I saw that it was white caulk. Did not look that good but the plastic flashing seemed to be well seated inside the metal trim and the small gaps were covered. Cleaned up the mess with WD 40. It cleaned up nice on the metal trim without scratching and it came right off on the plastic flashing. It also made it easier for the razor blade to glide on the glass surface without scratching and took off the wiped silicone. So the corner gap in the grey plastic flashing is white, so what. A month of camping and I'm sure it will turn a gross greyish color. A final glass cleaning with rubbing alcohol took off the WD 40 residue and the windows are sparkling clean now.