In order to unlock the DVD case, the least that you can get by with are two very strong magnets. The magnets pictured below are harvested from a hard drive. Generally, the older the drive, the larger and more powerful the magnets. Some new hard drives and some laptop drives have magnets which are too small and weak to use for this purpose.
The other item that can come in handy here is a screwdriver with a small regular tip. You can also use a knife, icepick, etc... as long as it has a tip small and sharp enough to grab the plastic.