That's a fantastic question, and honestly, the "best" system depends on your specific bin and habits. The goal is a seamless fit that contains all liquids and odors. Let's break down the top contenders.
First, consider heavy-duty drawstring bags. These are my top pick for most standard bins. Look for bags marketed as "leak-proof" or "extra strength" with reinforced bottoms. The drawstring creates a good seal when you tie it off. For bins with a perfectly round rim, elastic-top bags can be a winner, as they hug the rim tightly, preventing the bag from slipping in.
However, the real game-changer is often the hardware, not just the bag. A plastic bin liner holder or frame is a simple, cheap accessory that sits inside your bin. You clip your bag (even a standard grocery bag) onto it, creating a taut, open surface that holds the bag securely up and over the rim. This prevents bags from sagging in and getting punctured.
For the ultimate in leak containment, a bin designed with a built-in liner system is ideal. These often have a rigid inner bucket or a clamping mechanism to secure the bag. Some high-end models even use custom-fit compostable bags that match the bin's dimensions perfectly.
My final tip? Double-bagging for super wet waste. Use a thinner bag for food scraps inside a heavier duty main bag. And always ensure your bag is pulled taut over the entire rim—a saggy bag is a leak waiting to happen. The best system is the one you use consistently that fits your bin like a glove.