Tea: If you don't like coffee, you can use tea bags instead. Just place 2-3 tea bags inside the confined space. The tea leaves in the bags will not only absorb the trash can smell but will also release the natural aroma of tea.
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.