You can also buy a little magnetizer/demagnetizer, a plastic unit with holes for mag/demag of tools etc. Handy for magnetizing screwdrivers too! Something like this one: http://www.amazon.com/Magic-Cube-Magnetizer-Demagnetizer-Tools/dp/B003RY6YYM/ref=pd_cp_hi_1
And even an old plug-in degausser unit might be good for demagnetizing parts. They used to sell them to bulk-erase tapes.