Buried screws with broken heads can prove perplexing. Sometimes, there seems to be no way to get them out. But when it's absolutely necessary to remove a broken screw, you can use diagonal pliers or a screw extractor to back them out. Both are made to latch on. By using them surgically, pinpointing the broken screw, you can remove it with minimal damage.
Push the tip of the diagonal pliers hard into the wood surrounding the broken off screw. Open the jaws slightly and twist. Force the pincher of the pliers around the tip of the screw.
Pinch and clip away part of the wood surrounding the screw to get a good grip on the screw.
Clamp down on the tip of the broken screw as hard as you can. Twist the broken screw 1/4 turn counterclockwise. When the screw begins to raise up, get a better grip on the screw with the pliers.
Twist the screw another 1/4 turn. As the screw begins to back out, continue to get a better grip on it. Turn it counterclockwise 1/4 turn at a time until the screw is removed from the wood.
Hold the pointed tip of the screw extractor on top of the broken screw. Tap down on it with a hammer until you can feel the tip of the extractor bite into the end of the broken screw.
Slip the end of the T-handle over the end of the screw extractor.
Turn the T-handle slowly counterclockwise with your fingers. The pointed tip of the extractor will begin to thread itself into the broken end of the screw. Keep twisting the T-handle and extractor hard as the screw begins to back out of the hole.
Twist the T-handle until the screw and extractor come up out of the hole.
Always wear safety glasses when working with wood.