http://KenerlyDesign.com Have you got doors in your house that squeak when you open or close them? The primary cause of this squeak is the doors hinge pin. The pin is solid steel as is the hinge. They rotate on each other causing friction which you hear as a squeak.
As a remodeling contractor I see this problem constantly. I figured there has to be a better, affordable solution other than spraying the hinge with a lubricant. Spraying the hinge will temporarily fix the squeak, but causes a messy black residue on the door and trim.