Oh, that's a frustrating situation! A locked bin with a lost key is a common headache. Don't worry, getting a replacement is usually straightforward. First, don't try to force the lock or break the bin, as you'll likely be responsible for damage fees.
Your very first and best step is to contact your local waste collection company or municipality. They are the most common source for replacement keys. Check your latest service bill or their website for a customer service number or email. Often, the bins and their locks are proprietary, and the hauler keeps records of which key codes are assigned to your address. They can either mail you a new one or tell you where to pick it up, sometimes for a small fee.
If your bin is from a specific manufacturer (like Rubbermaid, Toter, or Simple Human), visit their official website. Look for a "Customer Service" or "Parts & Accessories" section. You might need your bin's model number, usually found on the lid or side. They often sell replacement keys directly.
For a standard, generic lock, a local hardware store might be able to cut a new key if you can bring them the lock's cylinder or a clear photo of the key code stamped on the lock itself.
In a pinch, if you need immediate access, your waste hauler might be able to unlock it on your next collection day if you leave it out. Just give them a call first to arrange it.
Pro tip: When you get your new key, make a copy right away and keep it in a safe place!