Step 1: Watch This Video!
Watch this video to see me open a combination lock with a soda can!
Step 2: What You Will Need
Just a can, and some scissors or a box cutter. Here I'll demonstrate with a combination lock, but this technique applies to several other kinds of locks, including padlocks that need a key to be opened.
Step 3: Cutting the Can
First cut off the top and bottom of the can. Next cut a strip of metal (for this lock I cut a strip slightly wider than an inch). Then cut the strip into the "M"-like shape shown in the picture. It's important to make sure you round the bottom of the middle section (the part circled in red). This will make it much more effective than if it's flat.
Step 4: Folding Into a Shim
Now take your "M"-shaped piece of aluminum and fold down the top. Once you've folded down the top, fold both sides upwards. You will probably need to wrap them around several times.
The tool you have just created is known as a shim.
Step 5: Shaping Your Shim
To achieve the proper shape for your shim, simply place it on the shackle and gently press so that it forms to the same circular shape.
Step 6: Opening the Lock
Once your shim is properly rounded you can slide it to the inside of the shackle's arch (make sure you are on the side with the locking mechanism, usually the left side). Press the shackle upwards and hold it there. While holding the shackle up, work the shim down into the locking mechanism. Once the shim is as far down as it can go, pinch it and continue to press it downward towards the mechanism as you push down the shackle. After this motion is finished, the shackle should simply lift and open, just as if you had entered the combination.
Opening a lock in this way will not damage the lock, but as you can see from the picture it will chew up your shim a fair bit. (Shims are usually only good for one use.)
Step 7: Shimming Other Kinds of Locks and Anti Shim Locks
Recently, Master Lock has been advertising anti-shim or shim-proof locks. These locks can actually still be shimmed, however they are a bit more difficult. Many padlocks that need a key to be opened have locking mechanisms on both sides of the shackle. For that type of lock you'll have to use two shims.
I hope this instructable will come in handy for you. Enjoy!
If you'd like to see more of my how to's and tutorials check out the links in the intro to this instructable!