I had second thoughts about answering this question because your all gonna think I'm nuts!
But here goes!
When I was first starting out in the professional world, I worked with an "Old Timer" electrician. One day we were changing the very large 1000 watt bulbs you see in parking lots. These bulbs have a larger screw in base than normal bulbs and they can get pretty hard to tighten. Anyway, as he was putting one in, he rubbed his finger on the side of his nose and then rubbed the outside of the threads on the bulb. The bulb went in the socket without any problem whatsoever. Since then, (30 years ago) I have been using this trick for every stubborn bulb I've come across and it has never failed me.
The reasoning - We all sweat! (Yes, even girls) and we produce oils. It just works out that this trick is just enough oil to get the job done in a pinch.
You can learn a lot from old timers!