The Ford Barn - Burnt Contacts on Voltage Regulator

Good evening, folks,

I was curious what your opinions might be on my voltage regulator. I had been having some charging issues and went about testing a few different parts of the electrical system, which is 6v, fyi. Took the generator off and found a broken brush spring; replaced that and bench tested it (hooked it up to power to get it to motor - worked). A-meter showed charging, but then a couple days later, stopped. Took the voltage regulator off to inspect contacts and saw that the contact points had burn marks on them. I had the cover off and figure maybe I got some oil from my hands on them or dust got in there. Car is running off battery - I found this out when I had trouble driving it at night with my lights on. (Dust is suspect because we just finished harvest... So it has been dusty, to put it mildly.) Is this repairable or do I need to replace the unit? It's a shame, because this is a US made unit that has presumably been on here since its restoration in '83-'85.