How do I use the magnetizer/demagnetizer and screw extractor kit?

Hi,

I just purchased the Magnetizer/Demagnetizer and Precision Screw Extractor set and had questions on how to use each. For the Magnetizer/Demagnetizer, do I just rub it against the walls of each? When I do, nothing seems to be happening. For the Precision Screw Extractor kit, for my iPhone screws, it never seems to quite get in the screws. How do I use each? Thanks!