Now that I got the bigger stuff sorted on this rig (new head gaskets, etc.), working on the annoying littler stuff. The center brake light fell off the rear glass. The outer housing mounts with a couple of nuts to a part that's glued to the glass itself. After 20 years, the glue (whatever was used) has failed. Crusty glue residue left on both the glass and light fixture. What's best practice on what adhesive to use? I assume I got to scrape off the crud residue that's there now.