That's an excellent and very practical question! A good lock can save you from the mess and hassle of scattered trash. There isn't a single "best" lock for everyone, as it depends on your specific needs—whether you're battling clever raccoons, strong winds, or simply want to deter casual rummaging. Let's break down the most common and effective options.
For keeping wildlife like raccoons and bears out, a sturdy latch with a carabiner or a simple padlock is often the gold standard. Look for bins with built-in lockable lids or add a hasp yourself. The key is simplicity and strength; animals are persistent but usually can't defeat a physical, metal lock.
If convenience is your priority, combination locks or keyed-alike padlocks are fantastic. You don't have to worry about losing a key, and one combination can secure multiple bins. They are great for families or shared spaces.
For the highest level of security and modern convenience, smart locks designed for outdoor use are emerging. These allow you to lock/unlock via an app, and some even send alerts. They are an investment but offer top-tier control.
Ultimately, the "best" mechanism balances security, weather resistance, and ease of daily use. A heavy-duty, rust-resistant padlock on a solid hasp is a reliable, cost-effective choice for most. For bins with flip lids, a integrated combination latch might be perfect. Assess your main threat (animals, wind, people) and choose a lock that is physically robust enough to counter it, while still making your trash day routine manageable.