That's a great question, and a very common issue, especially with public bins in parks or on city streets. That soggy, smelly mess at the bottom is not just unpleasant; it attracts pests, causes stains, and makes the bin much harder to clean. Over the years, I've found a few methods that really work to combat this.
The most effective long-term solution is to create drainage. If you're managing the bin yourself, you can carefully drill several small holes (about 1/4 inch or 6mm) in the bottom and along the very lower sides of the can. This allows any liquid to slowly seep out. The key is to place the bin on a permeable surface like gravel or a slotted concrete pad, so the liquid doesn't just create a new puddle underneath. For bins in paved areas, this method needs careful consideration of runoff.
For a simpler fix, use absorbent materials at the bottom. Before putting in a bag, line the bottom with a layer of old newspaper, cardboard, or even cat litter or dry sand. These materials will soak up minor leaks and spills, preventing a large pool from forming. It's a good practice to change this lining whenever you change the bag.
Proper bagging is your first line of defense. Always use bags specifically rated for trash, ensure they are not torn, and securely tie the top. For very wet waste like food scraps, consider double-bagging. Encourage users to drain liquids from containers before tossing them.
Finally, think about placement and elevation. Whenever possible, position the trash can under some cover to reduce direct rainfall. Using a slightly elevated stand or platform with gaps allows for air circulation underneath, which helps the base of the can dry out faster.
A combination of these strategies—like using an absorbent liner in a well-placed bin—will dramatically reduce liquid pooling, making trash collection more sanitary and less odorous for everyone.