Hogwarts Crest, or any other flat backed, Potter-themed item
Holding the magnet with the metal clamp, remove any casings from the magnets.
Lay out the magnets on the wrong side of the item to be magnetized.
Once deciding where each magnet will go, attach the magnets to the item with a glue gun.
Finish it off by removing any stray glue "hairs".
Allow to dry, then stick it to your fridge and enjoy!
© Nick McGill's tutorial was taken with permission from instructables.com.