I always dismantle my retired/knackered drives. Here's how: Once you've peeled the label off, use a Torx screwdriver to undo the screws, then remove the top casing. Now undo the collar holding the platter(s) and get medieval with them using something pointy.
As an added bonus, you'll find that every drive comes with a free neodymium magnet that's so strong you could stick a family-size saloon car to your fridge door.