A standard combination lock opens when the correct number series has been dialed in the correct order using the lock's dial mechanism. Usually this requires first turning the dial clockwise a couple times, then dialing the first, second and third numbers of the lock combination. Inside the combination lock there are rotors turning, and when the correct combination has been dialed in, the inner notches of the lock align and allow the lock to open. Many combination locks can be reverse-engineered to open by applying pressure to the lock's metal clamp.
Push or pull up on the lock's metal clamp. Apply enough pressure so that the metal clamp does not hang down at all.
Spin the combination lock dial clockwise until you hear a click. After the click, spin the dial clockwise again two numbers. This is the first number of the combination lock.
Continue pushing or pulling upward on the metal clamp and spin the dial counterclockwise until it stops. The number it stops on is the second number in the combination lock number series.
Spin the dial clockwise again until the lock releases. The number that the lock stops on is the final number in the lock number series.