Make sure it is 'almost dead'. You'll need a gauss meter, and it's difficult to find a good 'cheap' one. Any shop that repairs speedometers will be able to check the magnetic strength, and you'll know. They can possibly recharge it. I have looked over many 'cheap' recharging units, and strangely enough, many state they are not meant to recharge Alnico V magnets :?. If you have no common sense, you can expend a lot of time and effort and build your own. I would imagine it is just a large DC voltage; wrap the wire around an iron core, and have a magnetic 'gap'. But before I did anything, including sending it out to someone else, I would take a compass and determine which direction the charge is right now. That way, there can be no embarassing moments later.
"You can lead a horticulture, but you can't make her think!"