To Art's point about cleanliness -- some pics below of my windshield install. The first couple show just how much butyl may have been used to hold the previous windshield in place. The next two show partial clean up and all cleaned up and ready for new windshield install. If you let a windshield shop do the job, they are NOTORIOUS for 1) scraping PAINT off the pinch-weld with their windshield removal tools (which leads to corrosion later), and 2) for not cleaning all the butyl off before using their electric caulk guns to lay down the bead of polyurethane to seal the new windshield - which leads to leaks down the road.