Window guards protect children from falling out of windows and also act as a security deterrent. Most window guards attach to the window using one-way security screws. These screws are designed with heads that prevent regular screwdrivers from removing them. Although there are special screwdrivers available to remove one-way screws, they are not easily found in home improvement centers. Removing one-way screws from your window guard is possible, however, with a few tools you might already have around the house. Examine the head of the screw to determine if it has a thick head, thin head or is flush with the window guard. This helps in determining a method of removal.
Thick Screw Head
Cut a slot into the top of the security screw with a rotary tool and cutting wheel if the screw has a thick head. Insert the cutting wheel into the rotary tool and cut a slot into the top of the head. Do not cut more than half the thickness of the screw head.
Create the slot with a hacksaw, if you do not own a rotary tool. Attach two hacksaw blades to the hacksaw just as you would attach a single blade. As with cutting the slot with a rotary tool, do not cut more than half the thickness of the screw head.
Insert the tip of a flat-head screwdriver into the cut slot. Press down firmly on the screwdriver while turning the one-way screw counterclockwise until the screw is out of the window guard.
Thin Screw Head
Flatten two opposite sides of the screw head with a medium coarse file if the screw head is thin. Flatten the two sides just enough that you can pinch the flattened sides of the screw head with a pair of locking pliers.
Lock the jaws of the locking pliers around the flattened portion of the screw head as tightly as possible. Use rounded-jaw locking pliers instead of flat-jaw locking pliers. The rounded jaws achieve a tighter grip.
Turn the screw head counterclockwise with the locking pliers to remove the one-way screw from the window guard.
Flush or Indented Screw Head
Drill the screw head out with a titanium bit the same diameter as the screw head, if your security screws are flush against the window guard.
Pull off the window guard from the window once you drill out all of the screw heads.
Grab the remaining screw shanks with a pair of pliers and turn them counterclockwise to remove the screw heads from the mounting surface.