I have head the "lose connection" therory too, from an old boss of mine, but I have never bought in to it. I see it as more cause, than effect. The effect is most likely that the wiring to the lamp-holder will be over-heated, but not the cause, IMO.
What type of corrosion is it? Salt crystal type(water/condensate),rust (water), blackend copper type (heat/dis-simualr metal), white Al powder type (all/any of the above)?
Notice any spiders? Some make a fine web/egg sac that looks like corosion, and like to live in fixture bases. Sounds crazy, until you see them in there!
You say it has drain holes. But will it collect condensation before dew point in the morning and be wet?
Warning, avoid flamable or speading oils like WD-40, unless you like fire....
And anything like NoAlOx will dry up into hard clay.
I go for a 2 part solution:
(And a little mechanical abrasion edge of flat head.)
1.)Contact cleaner to get the stuff out.
2.)Then a silicone based spray lube.
I get both cans right next to eachother at the supply house, and often do the prosses in reverse because the cans are from the same company and look the same.
