Hasbro's line of "Star Wars" light sabres are essentially LED flashlights and are built in a very similar fashion. Taking them apart is a matter of removing a cap on the bottom of the sabre by hand and using a screwdriver to take off a few screws to remove the hilt.
Unscrew the bottom cap by hand and slide the batteries out of the light sabre.
Slip a flathead screwdriver under the panel with the power button on it. Slide the panel off with a gentle upwards motion with the flathead screwdriver.
Unscrew the Philips headed screws that were under the button panel. Pull the button assembly out by hand. The assembly will be connected by two wires.
Push the blade down toward the hilt to expose the battery bay and circuit board and allow the handle to slide off the blade. Use the flat head screwdriver to push on the attachment pins that anchor the blade to the top of the circuitry. The light sabre blade will come off the hilt but should have a power wire still attached to it.