Unlocking a door with a paperclip is a straightforward but efficient approach that may come in useful in emergency conditions when you do not have entry to a key. This technique works on doorways which have a regular pin tumbler lock, which is the commonest kind of lock present in houses and workplaces.
The trick is to make use of the paperclip to push the pins contained in the lock cylinder into the proper place, permitting the lock to show and the door to open. Whereas it could sound daunting, with a little bit of persistence and follow, anybody can grasp this method.