How to Open Combination Locks Without a Code
To open combination locks without a code, start by pulling up on the dial and turning it clockwise until you hear the lock click. Then, check what number you're at, add 5 to that number, and write it down. Next, set the dial to that number and turn it counterclockwise until you hear it click again. Then, write down whatever number you're at. Finally, set the first 2 numbers of the combination and then slowly turn the dial clockwise, testing each number as you go, until you find the third number and unlock the lock.
Familiarize yourself with the lock. A lock has three main components. The shackle is the U-shaped piece which attaches it to an object. The dial is the portion with numbers that turns. The body is the rest of the lock. If you hold the lock with the shackle on top and the dial facing you, typically the locking mechanism is on the left side of the shackle. Practice pressure. To find a lock combination you will need to pull up gently on the shackle. Too much pressure will make it impossible to turn the dial. Too little and the dial will spin freely. You should exert gentle pressure. This may take some practice. Find the first number. Pull up gently on the shackle and hold it in place. Turn the dial clockwise listening carefully until you hear the lock click. Start with a good deal of pressure and gently let up as you spin it around, until you meet resistance in only one place. If the dial catches every few numbers, you are pulling too hard. If it never catches at all, you are not pulling enough. It should catch in only one place, making a click. If the click happens when the dial is between two numbers, round up to the higher number. Add 5 to that number and write it down. This is the first number in the combination. Set the first number of the combination as your starting point. It may be helpful to spin the dial a few times before doing this to reset the lock. Turn the dial counterclockwise to find the second number. Maintaining gentle pressure on the shackle, turn the dial slowly. You should go all the way around the mechanism once before reaching the second number. The lock will bump and catch as you turn. Eventually the lock hit a point where it will be very difficult to turn. This stopping point is the second number. Note it on the same piece of paper. Try combinations. One method of finding the third number is to simply test every possible combination. Set your first two numbers as if you were ready to unlock. Then turn the dial clockwise very slowly, testing each possible combination. At this point there should be only forty possible combinations. You do not have to reset the first two numbers for each combination. Simply turn one number then tug. Repeat the process until the lock opens. Test for the third number. A different method for finding the third number is to test the catch. Spin the dial clockwise a few times to reset the lock and set it at 0. Apply upwards pressure on the shackle and turn the dial clockwise. The lock will catch several times, allowing for slight movement back and forth between two numbers. Write down the number in the middle. For instance, if the lock catches between 33 and 35, write down 34 on a separate piece of paper. This is not necessarily the final number. The lock will also catch partway between numbers. For example, the range might be between 27.5 and 29.5. If the middle number is not a whole number, such as 28.5, do not write it down. Lock combinations are always whole numbers. Proceed all the way around the dial, writing down all the whole numbers where it catches. You should have four or five numbers written down. Most of the numbers will fit a pattern, for instance all ending in 5. The one number that does not fit the pattern is the final number in your combination. Consider your lock. Recently made locks are designed to be shim-proof by the manufacturers, although in some cases it is still possible to pick them. This method will work better on older locks. Identify where the locking mechanism is. In order to use a shim properly you need to be working with the place where the shackle locks, as working on the hinge will not accomplish anything. Usually the locking mechanism is on the left side if you are looking at the lock with the shackle on top and the dial facing you. Cut an aluminum can. You can create a shim for yourself by cutting up a soda can.  Use scissors to cut off the top of the can, down the length and then to cut off the bottom. You should be left with a single piece of aluminum that was once the body of the can and is now a wide strip of metal. Cut a strip of metal. Turn the aluminum horizontally, so you are cutting the shorter side of the material. This piece will be used to make the shim. Cut a strip a little over one inch wide. If any of the edges are ragged, trim them. Make two curved incisions. Hold the small strip of aluminum horizontally and cut two curves from the bottom, somewhat resembling the letter U. Center the U in the middle of your strip. Do not cut all the way to the top. Make two diagonal incisions. Cutting from the bottom of the metal around a quarter of an inch from the base of the U, cut diagonally upwards to intersect with the top of the U and remove the triangles of material. The result should be a strip of metal that looks something like the letter M, with the middle of the M curved instead of pointed. This will be the shim. Fold the sides to make a handle. Turn the top of the metal downward an eighth of an inch or so. Then fold the sides upward around the top of the strip of metal. Folding the sides allows you to have a handle on the shim that will not cut your hand with a sharp edge. Gently fold the shim around the shackle of the lock. The U of the shim should face downward. You will want to wrap the shim carefully around the outside first so it molds to the shape of the shaft. When you have got the shape you want, turn the shim so the U is on the inner part of the shackle and your handle is on the outside of it. Remember to do this on the side of the shackle that has the locking mechanism. Press the shackle up as far as it will go and hold it in position with your finger. Using your other hand, slowly work the shim into the crack between the shackle and the lock itself. It will take a few minutes and you should not rush or force it. When you have worked it in as far as it will go, stop. Pop the lock. Pinch the shim with one hand. With the other hand, press the shackle down then pull it up. The lock should open. Locate the serial number. If your lock has a number stamped on it, write it down. Some locks will not have a serial number. Bring the lock to a distributor or retailer of the brand. Ask the distributor to contact the manufacturer on your behalf to validate your ownership of the lock and provide you with the combination. If the lock is attached to an object, for instance a box, retailers will likely not assist you. Be aware that the retailer may charge a fee for this service. Submit a lost combination form directly to the manufacturers. Visit the manufacturer's website to find out if they offer this service. Due to security concerns, manufacturers will likely not provide the combination over the phone or via email. You may be required to furnish proof that you own the lock, such as a notarized document certifying your ownership. Consult the owner. If the lock belongs to a school or business, the administrators may have a list of combinations based on serial numbers. Write down the serial number to bring to the main office. If the lock is attached to something, for instance a locker, be prepared to furnish proof that you have a right to access the belongings within the locker. 
Familiarize yourself with the lock. Practice pressure. Find the first number. Set the first number of the combination as your starting point. Turn the dial counterclockwise to find the second number. Try combinations. Test for the third number. Consider your lock. Identify where the locking mechanism is. Cut an aluminum can. Cut a strip of metal. Make two curved incisions. Make two diagonal incisions. Fold the sides to make a handle. Gently fold the shim around the shackle of the lock. Press the shackle up as far as it will go and hold it in position with your finger. Pop the lock. Locate the serial number. Bring the lock to a distributor or retailer of the brand. Submit a lost combination form directly to the manufacturers. Consult the owner. 