Turn off the hot tub as well as the breaker powering the spa on the main electrical panel. Take the cover off your hot tub and remove the filter cover as well as the filter by hand or use pliers.
Connect a garden hose to the drain spigot and turn on the drain valve. Allow the hot tub to drain completely, then disconnect the hose and shut off the valve.
Go to the electrical lines connected between the hot tub and the panel. Snip the lines with wire cutters if you do not plan to reuse the spa. If you are only temporarily disconnecting it, use a screwdriver and pliers to unhook the electrical connections.
Disconnect the plumbing lines using channel locks if you are reusing the hot tub in the future, if not simply saw the plumbing pipes in two with a hacksaw. The hot tub should now be totally disconnected from any peripheral water and power sources.
Remove the skirt around the tub spa bed using a screwdriver to unfasten the retaining screws holding the skirt in place. Alternatively, pull out any nails with a nail puller to free the skirt from the spa bed. You can now demolish or move your hot tub.