There is a key in the door lock. How to open it outside?

Now insert the key and try to turn it. If it can't be opened, pull out the key while rotating, and it will be opened under normal circumstances. If it has not been opened, continue to polish the key head, grind off the excess metal, and then try to insert it and open it. If it really doesn't work, it is recommended to find someone to unlock it directly, so as to ensure the integrity of the door lock and avoid spending more money after being tossed by yourself.