A single-pole switch has three wires connected to it, a hot wire, a switch leg and a ground wire. The hot wire is the feeder wire that is connected to the circuit breaker in the elctrical panel. This wire is connected to one of the side brass terminals of the switch.
The switch leg is the wire that feeds the light from the switch. When the switch is turned on, the electricity flows through the switch to the light. This wire connects to the other brass terminal on the side of the switch.
The ground wire is either the bare or green wire and is connected to the green-colored screw of the switch.
Using a screwdriver, unscreww the screws and remove the switch wires from the switch one at a time.