Lite_me said:
:huh2: Is this a good idea? I say keep the end of the barrel clean of oil/grease. I would suggest like JayR said ...
Each time you unscrew the head and break contact, the aluminum oxidizes. The oxide is a thin, very hard and brittle ceramic. (It is, in fact, used as sandpaper grit.) The next time you make contact, the aluminum oxide is shattered and the pieces embedded in the softer aluminum metal underneath (and in the gold of the PCB plating). When you unscrew the head again, the surface oxidizes again, and so forth. Eventually, you have a battleground of broken ceramic pieces and poor or no contact. You can of course restore operation again by sanding the aluminum surface to below the layer of shattered oxide pieces, provided that the PCB trace surface hasn't also been trashed too badly. But you can prevent or reduce the oxidation in the first place by keeping a thin layer of oil or thin grease on surface. This same phenomenon also occurs with tin.
There's so much lore about the function of grease and oil on contacts, I fully expect a lot of people to not believe this. That's ok. I've seen a photomicrograph of the surface of a tin contact after a number of matings, and it really impressed me. It's not surprising that the common lore seems more believable to people who haven't had that opportunity.
c_c