What do y'all use to clean the metal connectors that go into the bulkhead on either side of the fw?

Green is oxide, oxide as in oxygen...lack of oxygen is a lack of oxide. That's where the grease comes in, it should fully encapsulate the contacts blocking any O2 contact. Telco figured it out and our new house jacks all have a goo in them now that surrounds the contacts, looks like crystal clear jello. Its nice because it doesnt flow, it just displaces like a blob of kids slime and pops back into form when you pull the plug.