How to Open a Master Lock Without a Key

Updated April 17, 2017

The human brain is an incredible organ. Able to store, process and create an enormous amount of information, our brains are occasionally prone to forgetfulness. Perhaps you forgot your Master Lock combination, or perhaps you forgot the location of the slip of paper listing those secret numbers. Fortunately, there is way to open your Master Lock using common household materials, if you can remember where you put them.

Cut away the ends of a soda can. You may wish to wear leather gloves during this procedure to prevent from cutting your fingers on sharp edges.

Make a vertical cuy along the side to create a flat aluminium sheet.

Draw a large tear shape on the aluminium sheet with a permanent marker. Ensure the end of the tear is rounded, as opposed to pointy and sharp. If you have a guitar pick on hand, trace the pick with the permanent marker.

Cut out the tear shape (or guitar pick outline) with the scissors.

Place your new shim-rounded point downward along the inside of the Master Lock hook clasp on the right side.

Press the sides of your shim around the clasp and push the shim downwards into the lock. The shim will separate the hook clasp from the internal lock.

Pull the hook clasp away from the lock to open.


Some people recommend a complex M-shaped shim that requires a ruler and several drawn lines to create. The more simple shim described above will work just fine.


Never use this technique to open a lock that does not belong to you. Doing so can lead to fines and imprisonment. Note that newer Master Lock models come equipped with a shim blocker; however, if you purchased your lock more than a few years ago, you shouldn't have any problems.

Things You'll Need

  • Aluminium soda can
  • Black permanent marker
  • Scissors
  • Guitar pick (optional)
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About the Author

Aaron Kopf graduated from the University of Central Arkansas with honors in 2009, holding a Bachelor of Arts in communication. While enjoying his time at college, Kopf was published in The Echo and Vortex magazine.