That's a great question! Dealing with a smelly, damp outdoor trash can is a common headache. The best way to ventilate it is actually quite simple and focuses on promoting airflow to dry out moisture and let odors escape.
The most effective method is to drill ventilation holes. Using a drill with a 1/2-inch to 3/4-inch bit, create a series of holes in the upper sides of the trash can, just below the lid's rim, and also in the bottom of the can. This creates a "chimney effect," allowing fresh air to enter from the bottom and push moist, smelly air out the top. Be sure to drill from the inside out to leave smooth edges.
Always place your can on a raised surface, like bricks or a pallet, especially if you've drilled bottom holes. This prevents blockages and maximizes airflow underneath. Choosing a trash can with a loose-fitting or slatted lid, rather than an airtight one, is also helpful for passive ventilation.
Combine ventilation with these best practices: use heavy-duty, scented trash bags, sprinkle baking soda or cat litter at the bottom to absorb moisture and odors, and rinse the can regularly with a vinegar or mild bleach solution. Keeping the lid securely closed, even with vents, is crucial to keep pests out.
By implementing these ventilation and maintenance steps, you'll significantly reduce those unpleasant smells and prevent the sludgy moisture buildup that makes taking out the trash such an unpleasant chore.