Turn the key slot to the neutral position
Apply a lubricant to the keyway
Use tweezers or needle-nose pliers to grip the exposed key fragment
Use a broken key extractor tool if the fragment is recessed
Slide a thin jigsaw blade or hacksaw blade along the key fragment to catch and pull it out
Use a strong magnet if the key is magnetic
Tap the lock lightly to help the fragment shift outward
If the fragment is deep inside, remove the lock cylinder if possible
Call a locksmith if the fragment cannot be removed safely