An unused power switch in your home can be inherently safe left intact for the most part. However, in some circumstances, a connected power switch may post a hazard when an electrical device isn't connected to the circuit and may pose an electrocution or fire hazard should the switch be accidentally activated. In such circumstances, the switch may be easily removed and a wall cover placed over the switch opening to prevent access to the interior wall wiring, which terminates in the switch box.
Turn off the power to the light switch circuit in your home by turning the circuit breaker switch to the "OFF" position. Close the breaker box cover and lock it, if possible, to prevent others from turning the switch on while you are working to remove the switch.
Remove the exterior switch faceplate screw with an appropriate size and style of screwdriver. Lay the screw and the faceplate off to the side.
Remove the interior switch mounting screws. These screws can be seen going through the metal tabs on the top and bottom of the switch, securing the entire switch assembly in place against the wall. Lay the screws off to the side and then gently pull the switch assembly from the wall so you can access the wire terminals on the switch easily. Unscrew all of the wire mounting screws fully and then use a pair of needle-nose pliers to remove the wires from the screw posts.
Straighten the wire ends that were connected to the switch screw posts, if they are bent or curved, using your needle-nose pliers. Straighten them enough to allow you to screw wire nuts onto the wire ends completely so they cannot fall off.
Match up wires of the same colour. There will be wires on the left side and wires of the same colour on the right side of the wall. Twist together left and right: for example, red to red, black to black, white to white, green to green. This is necessary to allow electricity to flow to other wall outlets and switches further along on the electrical circuit. Depending on the size needed, screw either a 10 AWG or a 12 AWG wire nut tightly over each twisted pair.
Gently fold the wires into the wall so that the wire nuts are separated from each other by an inch or two as an additional measure to prevent any of the wires from shorting together should any wire nuts fall off over time. Though this is highly unlikely, it is best to ensure they are separated for additional peace of mind. Screw the interior mounting screws back into the holes so they are available if installing another light switch into the receptacle in the future.
Place your wall switch cover over the switch opening and use a screwdriver to screw in the exterior cover mounting screw firmly into place. Turn the power to the circuit back on at the circuit breaker.
Don't over-tighten wire nuts when screwing them onto the twisted wire ends. The copper wire in household wiring is a soft metal and over-tightening wire nuts will strip the metal ends, possibly allowing the nuts to fall off over time. Finger-tight is ample when installing wire nuts.
Always splice together wires of equal colour: for example, red to red, black to black, white to white, green to green. Never connect two different-coloured wires together as this will pose a fire hazard or repeated tripping of your circuit breaker or fuse.