That's an excellent question! Keeping metal trash cans from rusting is a common concern, and thankfully, there are several straightforward steps you can take. First, consider placement. If possible, position your cans under a roof overhang or in a shaded area to minimize constant exposure to rain and direct sunlight, which accelerates wear. A simple waterproof cover is a great investment to shield the lid and upper body from the elements.
The single most important habit is regular cleaning. Don't let moisture, dirt, and debris—especially from garbage—sit at the bottom. Hose out the can monthly and scrub it with a mild detergent and a brush. Always let it dry completely upside down before putting a new bag in. For cans that are already showing minor rust, sand the spots with fine-grit sandpaper and apply a touch-up spray paint designed for metal.
For long-term protection, applying a protective coating is key. You can use a clear automotive or marine-grade wax/sealant on the outside. For a more robust solution, a spray-on rust-inhibitive primer and paint made for outdoor metal will create a durable barrier. When purchasing a new can, look for options made of galvanized steel, aluminum, or powder-coated metal, as these have built-in rust resistance. A little proactive care significantly extends the life of your outdoor bins.