Why? You're being helpful. That's what we're here to do.
Sounds like you have corrosion in the connectors or damage near the bulkhead plug or the valve.
The tin plating on Weatherpak tower terminals to the valve corrode if they're left unplugged.
The brass Packard terminals corrode when the black dielectric goo that GM sprayed the plugs with degrades.
Caig DeoxIT D5 and a set of carburetor cleaning brushes might be a worthwhile investment.
I've seen small diamond files for cleaning Canon plug terminals but I figure if they're that corroded it's time to replace them.
Carb Cleaning Brushes on Amazon
I can get Deoxit D5 at a guitar store. Musicians use it to clean the plug contacts on their guitars, keyboards, mics, and amps. I use it on other electronics. I used to pick it up at a local Radio Shack but they're disappearing. :-(
Be sure to get the DeoxIT D5. They make a "fader" cleaner and lube for potentiometers that won't work as well on connector terminals.
Once the bulkhead terminals are treated with Deoxit, scrubbed some, and sprayed again it wouldn't hurt to add some fresh dielectric grease.
CRC 02083 Spray Silicone Dielectric Grease would be a reasonable choice. You can probably use a lube straw on this to reach into the female terminals and treat the bare wire at the back of the connectors.
I wish I knew what that black dielectric grease that GM sprayed into them on the assembly line was. It protects things for half a century and more. I've taken apart the bulkhead plugs on late 1960's GM, AMC, and Chrysler cars and found the terminals look like new.