What part needed the D100L application?
It was just the pins. As I recall, they were shiny with no sense of tarnish or grime, so I wasn't going to bother trying to clean them. When I started to clean them, I almost thought that there was some substance on them as if the goal of a previous owner was to keep them from getting tarnished. I put the Deoxit on a cloth and just kept rubbing the pins for a few minutes. It certainly did the trick.
