Unplug the sink disposal power cord from the dedicated outlet under the sink. If your disposal does not have a power cord and is hard-wired into your home's electrical system, turn off the circuit breaker to the disposal.
If your unit is hard-wired. find the rectangular access cover for the electrical wire on the side of the disposal. Remove the screw securing the access panel to the unit with a Phillips-head screwdriver.
Turn the wire nuts connecting the disposal wires to the house wires counterclockwise with your fingers. Separate the wires from each other. Loosen the clamp securing the conduit for the house wires to the side of the unit with a flat-head screwdriver. Pull the conduit away from disposal, bringing the house wires out of the unit. Twist the wire nuts over each individual house wire until you are ready to connect another unit.
Place a bucket under the sink disposal to catch any residual water. Loosen the screw on the clamp securing the dishwasher drain hose to the side of the disposal with the Phillips-head screwdriver. Pull the dishwasher drain hose away from the unit.
Remove the screws securing the drain discharge tube to the side of the disposal with a socket wrench. Loosen the nut securing the discharge tube to the sink drain pipe with a pair of slip joint pliers and pull the discharge tube away from the disposal.
Find the end of the snap ring securing the disposal to the sink mounting flange. The end of the snap ring folds over the ring and is clearly visible. Pull the end of the snap ring up with a flat-head screwdriver to loosen the snap ring.
Twist the disposal counterclockwise with your hands and pull it away from the bottom of the sink. If you are replacing the unit, remove the bolts securing the disposal mount with a socket wrench and remove the mount from the sink drain basket.