I use a magnet to magnitize the sewing needles I put in my PSK. Before I store them I place them on a piece of paper floating in a bowl of water. I then use a red marker to indicate which end of the needle points north. I got the idea from reading how POW's in Germany would make escape compasses by placing thin pieces of metal on the magnets at the back of camp PA speakers.

I EDC a real compass and have a button compass back-up in my PSK, the magnitized needles are just my "back-up to the back-up"!

Mike