Before the glass installation can begin, the window channel must be clean of all the old sealer, and any rust needs to be repaired and/or treated. Any bare metal should be sealed with a good epoxy primer to prevent future corrosion. Our '71's window channel was in great shape. Now is the time to make sure the reveal-molding clips are intact and in good condition. We replaced all of ours with a kit from R/T Specialties.