How to get magnets from a dead hard drive

Tools
Torx bit or Dremel with cut off wheel
"5-in-1" painter's tool (or other prying device)
Flat head screw driver to pry
Vice (handy but not necessary)

Probably the most asked follow question about making stir plates is "Just how do I get the magnet out of the hard drive again?". It's relatively easy once you know where to look.

Hard drives are slightly different based on manufacturer, but in general the case is held together with security screws in a star pattern. If you have a torx set, opening the case is as easy as unscrewing them with the proper sized bit. If you don't have a torx set you can employ a variety of methods, but I prefer the Dremel. Use a cut off wheel to cut a channel through the top of the screw allowing you to open with a standard flat head screwdriver.
After removing the security screws open the case. On the inside you will see shiny platter and read/write head (think old turntable and LP's). The read/write head is electrically controlled by magnets, which is what we're after, so look under the arm (you may need to remove a few more security screws here). Use a flat head screwdriver to pry the housing off, here you will see just how strong these magnets are! Don't afraid to use a little force or break some of the plastic bits, the drive already worthless.
Once you remove the housing with magnet (note some hard drives have two magnets) you need to separate the magnet from the metal housing. I put the metal housing in a vice, then use a 5-in-1 painter's tool to pry them apart. Sometimes it takes some gentle persuasion with a hammer. Once separated you have a nice and very powerful magnet perfectly ready for its new life in a stirplate.
And that's all there is to it.