When a person sprays Febreze on carpet, furniture or fabrics, a corn starch derivative called beta-cyclodextrin surrounds the molecules that cause the odor. As the Febreze molecules surround the source of the smell, they prevent the odor from getting into the air and spreading the scent.
Febreze doesn't totally eradicate an odor, but it does more than simply mask the smell. As the Febreze dries, some of the odor molecules cling to the beta-cyclodextrin. When a water-based cleaning solution is applied to the source after drying, more of the odor-causing molecules get picked up. Repeating the spraying and cleaning steps further removes smells.