As many home do-it-yourselfers already know, few things are as frustrating as a screw that refuses to budge. If the screw is inserted in metal, has been exposed to moisture and hasn't been removed for an extended period, rust is more than likely the cause for its stubbornness. Fortunately, removing a rusted screw is possible with just a few basic tools.
Spray the rusted screw liberally with penetrating oil or commercial rust remover. Gently tap on the head of the screw and surrounding metal with a hammer. The tapping will cause vibrations that allow the oil or rust remover to work around the threads of the screw. Allow the penetrating oil or rust remover to remain on the screw for five to 10 minutes.
Tap on the head of the screw and surrounding metal with a hammer. Using a hammer a second time will help break the corrosion free from the screw, further loosening it.
Position the head of a screwdriver into the slot on the head of the screw. The screwdriver must fit snugly in the slot. If the screwdriver is too big or small, it may damage the head of the screw and make it more difficult to remove. Firmly hold the screwdriver in place with your non-dominant hand. With a hammer in your dominant hand, tap the handle of the screwdriver, forcing it securely into the head of the screw. Set the hammer aside.
Press down on the screwdriver and turn the screw clockwise, as if to tighten it. This will help loosen any remaining corrosion holding the screw in the metal.
Attach a pair of locking pliers to the handle of the screwdriver. The pliers will give you extra leverage when turning the rusted screw. Push down on the handle of the screwdriver with one hand. With the other hand, grasp the locking pliers and turn the screw counterclockwise to loosen and remove it. Reapply penetrating oil or rust remover as needed.
If the screw won't budge, use a tool known as an impact driver. A hammer will be needed to hit the impact driver. The impact of the hammer forces the driver to dig into the head of the screw and turn it simultaneously. You may also use heat to loosen a severely rusted screw. Use a torch to slowly heat the metal surrounding the screw. As the temperature increases, the metal will expand, allowing you to turn out the screw. Be aware, however, the heat may damage or discolour the surrounding metal.