Simply grasp one end of a bar with pliers and squeeze. Then touch the bar to something magnetic such as a ferrous pair of pliers :P The idea is to deform the casing slightly which allows the magnet to pop out. Mine were only pressed in - no glue.
Be careful when putting them together - they are capable of self destruction if you snap them together. And once they are together -- its a PITA to get them apart (I used pliers ;) ).
Yes, I know you can find magnets around for free.... but if you can find this quantity/quality - I'd be impressed.