Human life is famous for its unpredictability and sneaky surprises. So every adult has had to deal with the question of how to open the door, if the key in the lock is broken, at least once in his life. Let's say at once that the situation is unpleasant, but not tragic. And quite often it can be "destroyed" on its own, using a tool for a safecracker.
So, your key is broken and remains in the lock. Do not panic, but assess the incoming conditions. If part of it sticks out of the lock, consider yourself lucky. We knock on benevolent neighbors and borrow tools from them - the simplest ones, they can be found in almost every household. Then use one of the ways how to open the lock with a broken key: 90% of the time something from the list works. The main thing is to dab some grease on the lock "latch" before breaking it. It is better to do it with a syringe, so include it in the list of necessary tools.
Now let's move on to the main part of the work on opening your own home. Friendly advice: enlist the help of a sympathetic neighbor - it will definitely not be superfluous. But the volunteer must be all right with patience, otherwise he will become your secret (or even obvious) detractor for life.
Method #1. Fix the protruding splinter with pliers and start rocking it slightly left and right. Do not forget to pull the pliers toward you. Quite often such manipulations are successful.
Method number 2. It is useful if the splinter is tightly seated. Take a jigsaw blade, insert it into the hole with the teeth upwards and try to pull it out. The method is reliable, but it may take several attempts.
Method #3. Relevant if the key itself is quite wide. Drill a hole in the wreck, screw a self-tapping screw into it and pull the construction with the pliers.
If the key is broken in the lock, how to get it out - this is not the biggest problem. In the apartment and still need to get somehow. When someone else has the keys, call and report the trouble. While you retrieve the chip, the owner of the duplicate will come and rescue you. If there is no other set, or it is locked in the apartment, or its owner flew to Bali to rest, even with the extraction of the breakage is not worth the trouble: call the emergency break-in specialists, ask your neighbors for a chair so you do not have to stand until the rescuers arrive, and start learning zen.
Somewhat different approach is required when the key is broken in the ignition. Self-action is acceptable only when there is a pretty solid piece of key sticking out of a well. Apply method #1 - but very carefully, gently and lovingly! Remember, that restoration of paints on a car is not a cheap treat. If the key is broken off against the door, it is better not to fill your head with amateurism and look for the number of a good mechanic in the phone book. Emergency lock picking service works 24 hours a day in Kiev. Even if you are in a hurry, remember the existence of public transport. Or call a cab - in any case, you will spend less money than for the car paint resuscitation and lock replacement.