Turn off the power to the garburator at the switch and circuit breaker
Check for a reset button on the bottom of the unit and press it if needed
Use a flashlight to look inside for visible blockage
Remove any visible debris with tongs or pliers, not your hands
Insert the hex wrench into the bottom center slot and turn it back and forth to free the impellers
Run cold water and test the unit briefly after freeing it
If it still hums, turn off power again and repeat the wrench step
Use a plunger on the sink drain if the clog is in the drain line
Disconnect the trap under the sink and clear it if necessary
Reassemble the trap and check for leaks
Avoid using chemical drain cleaners
Call a plumber if the unit is jammed, leaking, or still not working