I'm in the process of evaluating some pre-1978 GE IAC relays for possible refurbishment. All of the relays current element wiring (solid core with a crimped ring lug) that terminates at the rear of the relay exhibit a brown residue (sticky to the touch and will leave residue on the fingers) that has wicked down to the ring lugs. I'm thinking the insulation has degraded from age and installation in a hot ambient temperature environment. It may be PVC plasticization; later IAC's use a different insulation/sleeving.
Have any of you run across this issue?
Some pics. Looks like PVC plasticization insulation breakdown. Passed hipot and IR tests though.