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Combination padlocks tend to only lock on side while keyed locks usually have a double-lock shackle. To open a single shackle lock, you create a shim by cutting out a piece of aluminum shaped like the letter M. The middle indentation of the shim is inserted in the space between the lock body and shackle and then the shim is turned while working the shackle up and down until the shim has moved around to the other side of the lock into the locking mechanism. Once the shim is there, use it to push the locking mechanism out of the way and open the lock. Check out how to open a padlock with just a pop can in the link below.
