If you have an old speaker laying around it will contain several magnets that you can re-purpose for other projects. The larger and more powerful the speaker the more powerful magnets it contains, and it will take increased effort to remove them. Removal is simple but does require some tools—and can be dangerous, due to heating up the magnets in the process.
Dismantle the speaker cabinet by removing the front grill. Usually these will pop off if you pull them gently. Otherwise, pry it off with a flathead screwdriver.
Unscrew the speaker if it is mounted with its screws facing outward. Otherwise, unscrew the back panel and then unscrew the speaker from the rear.
Remove the speaker from the cabinet and clip any attached wires.
Cut the speaker cone away from the metal mount using a utility knife or other sharp object. Remove all the excess material to prevent smoldering.
Place the speaker on a heat-resistant surface and apply heat with the heat gun gradually, making sure to heat the rear of the speaker evenly. This is where the magnets are located, which you can test by seeing if they will attract your screwdriver.
Take a break after a few minutes and put on your heat-insulated gloves. Use the chisel to apply pressure along the outside of the magnet edge and tap gently with the hammer. Do not force it as it may need to be heated longer.
Gently remove the magnets or, if they won't budge, reapply heat for a few more minutes to further loosen the glue holding them together. After a few minutes repeat Step 6.
Allow the magnets to cool before handling them. They will remain hot for some time.
Things You'll Need
Screwdrivers, Phillips and flathead
Heat gun or other heat source
Heat insulated gloves
Small chisel or dull kitchen knife
If available, use a vise to hold the speaker in place while you heat it and try to remove the magnets.
Do not strike magnets forcefully as it will lessen their charge.