Turn off the power to your garbage disposal. This will ensure the disposal does not start up while your hand is down the drain.
Remove the waste pipe connection. Use a screwdriver to loosen the screws holding the flange, and pull the pipe from the garbage disposal. If you have enough slack in the waste line, you will not have to remove any wires connecting to the disposal.
Insert your screwdriver into the dog-ear nut connecting the garbage disposal to the sink. Turn it counter-clockwise to disconnect the nut.
Reach into the drain, and pull out the old, worn-out splash guard.