I’m sure it’s happened once they have been broken a key into a lock and do not know how to remove it, but calling a locksmith. If you can see inside the lock and still see that is the key, it is possible that you can remove it without anyone’s help .Most keys, even brass and nickel-plated keys, will eventually wear out and break along any of a key’s cuts. But some conditions will speed up the process such as:
The key has one or more deep cuts which become the “weak point” of the key. After so much use (or just a little abuse) the key will break at these points. Having a deep cut as the first cut (next to the head of the key) can be real trouble but a deep cut in the middle of the key can cause big problems too;
The key is made of a light-weight material not suitable for everyday use. Keys cut on aluminum blanks are a prime example. They will also break at a deep-cut “weak point” only sooner. Identified by their light weight and either grey in color or sometimes bright colors such as red, green, blue or gold.
Usually before a key breaks, one or more tiny cracks will appear by the cut about to give way. You may want to check your keys right now – at least the ones that you use and depend on every day. If you see a tiny crack being formed by one of the cuts or if the key is bent or misshapen in any way, go to your nearest locksmith or key shop and get another one or two made. And just to be safe, don’t carelessly toss the old key away. A new key could be made from the pieces and used to access your property.
To do so, the first thing is that you have the tools necessary for any of these things and so do not have to make a million boxes. Collect what you will need only two things: a needle nose pliers and spray lubricant.
Many people prefer to use WD-40 or 3in1 for use as a lubricant, and you can get at a hardware store and elsewhere. This really is very good and serves many maintenance work, so be one always close. To prevent the call break into any door and avoid having to remove it, put some 3in1 locks every three months. If winter in your country to the point of freezing, do it monthly. Clean excess.
Now, continuing to take the key, put the spray lubricant or a few drops of 3in1. Give a few minutes for it to work well. Take the tweezers and put it into the lock and a firm grip when key piece pull out. If it does not, try a couple more times without applying excessive force and giving more time to the lubricant or more applications.
If you try 3 or 4 times and did not get it, then change the doorknob or call your locksmith. The knob can also be changed by you. Here’s a tutorial on how to do it .