Once the pitting has started other than cleaning the rust off and protecting the metal, there is nothing short of re-plating or replacing you can do. A little WD-40 with baking soda on the tooth brush works well. (Use liberal amounts of elbow grease and wrist oil as always.)
Over on the bass forum someone suggested using a pencil eraser to remove the rust from the poles of the pickups. Then a touch of something to displace water. All you need is a little bit. (WD-40, vegetable oil, ect.)
Another product for protecting metal that I love is Teflon spray from Remington. It is a good water displacing, metal protecting, lubricating spray. My dad, a sportsman, described it as being "Slicker than greased Owl Sh*t that's been boiled with okra."
That's pretty slick.