Most of us are familiar with secondhand smoke (tobacco smoke from a burning cigarette, cigar or pipe). Third-hand smoke (THS), by contrast, is not as well known. Third-hand smoke is the toxic residue that remains on clothes, furniture or in dust after tobacco use. Third-hand smoke is also the smelly odor in a room, or on a smokers clothing. Smokers carry THS around with them wherever they go, and any object they touch will be contaminated with it. Third-hand smoke can be inhaled or ingested as dust and can be absorbed into the skin by direct contact.