i have seen and performed a trick by jeff mcbride from a book called, magic for the complete idiot.
it has worked for me, and to everyone else the effect is a s follows: Th magician takes a pen and balences it on a waterbottle, he mysteriously makes it follow his finger and spin.
Just get a square of fleece, and put it in your pocket, when the time comes, you shoud ask the audience to inspect the bottle, and while they are preoccupied, you should rub the pen on the square of fleece. Then take the pen and place it on the top of the bottlecap but, once you let go, you must not touch it again, or the charge will dissipate. if you put you finger near it, it should be attracted to it ans turn towards it.
im not sure of your version, but this is one that definately works.....