Rally dash redo
Steve, get a product called alumaprep 33, some small steel wire brushes. Small plyers, a pin extractor for removing the male and female spades, and some Tri Sodium phosphate.
Unpin each spade or barrel connector one pin at a time from the plastic housing. Soak the connector pin in alumaprep 33 , then scrub with the small steel wire brush to polish up the pin or connector. Rinse the end you just scrubbed and polished in tri Sodium phosphate and water. Dry with compressed air. Using the plyers, slightly squeeze the female connector to make it fit tight again, rebend the tab so it locks back into the plastic housing if applicable, and repin. Remove next connector from the housing and start the process over.
Alumaprep 33 is a mild acid so use latex gloves and some protective eyewear. You might try apple cider vinegar with this process, and still would use the Tri Sodium phosphate and water as a neutralizing rinse
If you have a schematic that lists the pin location in each connector cavity, and a good camera on your phone, you can unpin a row of wires and repin them back in the same spot. I would only replace a connector if it and its wire was burnt or overheated.
Take your time. I redid a harness once like this including rewrapping it with the self fusing factory style black tape. It took me awhile to redo it.
Hope this helps
Matt