Coffee: Ground coffee has a nice, crisp natural aroma. Just put about a cup of ground coffee in a flat, uncovered container. Place the container inside the confined space for several days. If the bad smell is extremely horrible, put more ground coffee. The area will smell of fresh coffee for many days.
Baking soda: This is also a good absorbent. Put a generous amount of baking soda in an uncovered container (the size of the container depends on the size of the confined area) and leave it for several days. Remove the baking soda and replace it with new one and leave it for a couple of days. Continue replacing the baking soda until it has cleared the trash can smell.