Master Lock offers a variety of padlocks, U-locks and combination locks. The standard way to open the Master Lock is to insert a key into the keyhole and turn it as you would any other lock. However, it's also possible for you to break open a Master Lock if you don't have the key. This method is good if you need to open the lock quickly, and picking the lock would take too long.
Cut the metal loop off the lock with bolt cutters. Place the bolt cutters around the loop of the lock and apply pressure until the cutters break through the loop.
Break a Master Lock U-lock with a hammer. Hit the loop of the lock directly at the curved portion of the loop. By hitting the right spot, the loop can be released from the body of the lock. This may take a few attempts to find the right spot.
Break a combination lock with a screwdriver or shim. Pry the numerical dial off the front of the combination lock. Slip the screwdriver or shim under the numerical front and apply upward pressure. Break the center metal piece of the lock. Stick the screwdriver or shim in the hole on the front of the lock and move it around until the metal piece is loose and the loop of the lock releases.
Breaking a lock will make it unusable, so do this only if you have to open the lock quickly and don't have the key.