Did you try to open your front door with your key, but the key unexpectedly broke off in the lock? If so, you'll need to know some tips to get that key out of there.
Apply A Lubricant
No matter what technique you use, it is important to apply a lubricant to the lock to help the key move. A simply spray lubricant like WD-40 will do the trick with getting the broken key loose.
Use An Extraction Tool
You can purchase a special tool that is designed to extract broken keys. Your local hardware store may not have it in stock, but they are easy to find online. The tool has a very thin edge that you will stick into the lock on the top side of the key, and it is designed to hook on the top edges of the key that are rough. You should hopefully be able to pull the key out with a little bit of trial and error.
Use A Thin Jigsaw Blade
One tool that you can find at your local hardware store is a thin jigsaw blade. It is possible to only spend a few dollars on this tool, which will work very similar to a key extraction tool. Grab onto the blade with some pliers so that you can get a good grip on it, and then work it into the top part of the lock to grip the key's edges. It is definitely worth a try if you have one of these blades on hand. A small blade is always going to work better, so try to find the smallest blade possible.
Remove The Cylinder
If you are able to remove the lock cylinder, you may be able to tap the key out with some force. Try forcing the lock cylinder against a hard surface to get enough force to get the key to push outward. If you get even a small amount of the key to come out, you can use pliers to pull the key the rest of the way out. If the lock cylinder is open on the opposite side, you can use a thin object to push the key out from the other side.
Use Stiff Wire
It is possible to use two pieces of stiff wire to act as tweezers. If you can get the wire along both sides of the broken key and apply pressure to the sides, you may be able to lift it just far enough out to pull it out the rest of the way with pliers.
If the above options don't work, it's time to contact a professional. Reach out to a locksmith that offers lock repair in your area for more information.