It is easy to forget the combination to a lock. Fortunately, Master Lock offers a way to change the combination on most of its models. This tutorial is specific to one of the most common Master Lock padlocks, model 646, and similar versions. Within 30 seconds, anyone can reset the numeric code.
Open the Master Lock.
Rotate the shackle approximately180 degrees so it is parallel with the body of the lock.
Push the shackle in, as though you were closing the lock, but the lock will not close because the shackle is parallel to the body.
Set the new combination by holding down the shackle while adjusting the metal digits to a desired code.
Release the shackle, and the new combination should be set. Be sure to test the Master lock before locking it on to an item.