The windshield in my “53 had leaked onto and into my headlight switch for so many years that when I got the truck, the knob would not even pull out. I pulled the switch out and pulled it apart at the kitchen table (that made the wife happy). It was a mess. I gently cleaned everything and applied some dielectric grease. I used a battery powered test light as I reassembled the switch to make sure it was working right. The switch now looks and works like new.
