First step is to check the alignment. The key can only be removed from the lock when the jagged or cut side is aligned with the top of the cylinder. So, in this case, try turning it 180 degrees. On some occasions, the broken key won’t come out because the bottom pins don’t align properly, and this occurs if the retaining cap is loose. Try and make sure the key is in the same position it was in when you inserted it. Next, with your fingers, try pushing on the face of the plug, and attempt to pinch the key out. Tip: You can use the tips of your fingers on the other hand to push in on the plug while you try to pull the key out.
If this doesn’t work, grab a pair of needle nose pliers. Try to grab the broken key with the pliers and get a good hold to pull it out the rest of the way. You may have to attempt another method to get to this point if there is not enough of the broken key to grab hold of. If you don’t have needle nose pilers to hand, alternatives include a pair of sharp scissors or even tweezers (but with caution!). You don’t want to push the broken half into the keyway further.