I have used a conductive grease made by Nye Co. It has fantastic conductivity. It is a carbon/synthetic compound. We used it in IBM production of a round shaft / tangential contact, (both gold). Because the power supply was a constant current variety, we had lots of problems with the contacts. However, the grease fixed all those problems. Unfortunately, it's about $60 an oz. Anybody want the part #? ron N4UE