Discovering antiques with their secrets locked away can be frustrating if you don't have the key. Whether your bought the antique from a dealer or an individual, or whether it was passed down to you from a family member, finding out what's inside may not be easy without the key. There are a number of ways you can open an antique lock, but some of them may require damaging the antique to get inside.
Contact a local antique shop and ask whether they have an antique key-finder's program. Many antique shops specialize in locating antique keys and may even have a key that fits your antique lock. Present the antique shop with any information about the antique, especially details printed on the lock. This helps them narrow down the maker of the lock and the type of key required to open the lock without damaging it.
Pick the lock. Most antique locks tend to be far simpler mechanisms than the locks designed today. In order to pick the lock, insert a straight tool from a lock-picking kit, apply pressure and attempt to turn the lock. You may have to try a couple of different tools until you find the right one that works in your lock.
Remove the lock. Many locks are attached with hinges that can be removed with a screwdriver. Unscrew the screws holding the hinges and lock in place carefully, as applying too much pressure may strip the screws so you cannot reattach the lock after opening it.
Force the lock open. If you are not worried about preserving the antique, and simply want to open the lock, you may be able to pry it open with force. Wedge a flat-head screwdriver between the openings and apply force to pry open the lock. You may also be able to forcefully remove the lock itself by prying the edge of the screwdriver underneath the lock and lifting it with force away from the antique.
If you have little or no experience picking a lock, and you don't want to damage your antique, contact a professional locksmith. Many locksmiths may not only be able to open the antique lock easily, but can also create a replacement key so you can open and close the lock in the future without damaging it.