That's an excellent and practical question! For public outdoor bins, the primary goal of a locking mechanism isn't to stop determined humans but to prevent animals like raccoons, dogs, and birds from scattering trash. Based on that, the best mechanisms are simple, durable, and require a specific human action to open.
The top choice is often a locking bar or latch system operated by a foot pedal or a hand lever. This design keeps the lid securely closed by default. Only when a person steps on the pedal or presses the lever does an internal bar retract, allowing the lid to swing open. Animals can't replicate this action. These mechanisms are usually made of heavy-duty, rust-resistant metal and are integrated into the bin's structure for longevity.
Another great option is a recessed or covered locking tab. The latch is hidden under a lip or requires pushing a specific panel to release it. This design frustrates clever paws and beaks while remaining intuitive for people.
Avoid simple flip lids, bungee cords, or basic hasps, as animals quickly learn to defeat them. The ideal lock is robust, weatherproof, and minimizes moving parts that can rust or break. Ultimately, investing in bins with these built-in, animal-resistant locking systems saves money on cleanup and keeps public spaces cleaner and safer for everyone.