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.
Vanilla Essence: Pour several drops of vanilla essence on a couple of cotton wools. Toss the cotton wools inside the confined spaces nearest your trash can. Leave them for several days and you will notice that the area smells nice, or at least smells nicer.