The Long Answer:

Thirdhand smoke is the chemical residue from tobacco smoke. It is also called “tobacco smoke residue” or “stale tobacco smoke.” The chemicals in thirdhand smoke are toxic to humans, especially children. It can linger for years in dust and on household surfaces. It can also become embedded in carpets, furniture, clothes, and building materials. It is difficult and expensive to remove.

Removing thirdhand smoke from your home includes three approaches: cleaning washable household objects, cleaning unwashable items, and cleaning your home’s structure. 

Cleaning Washable Household Objects: Removing thirdhand smoke residue from household objects, like dishes, toys, clothes, and blankets, can be straightforward.

• Clean clothes, toys, and bedding in a washing machine. Depending on how polluted the fabrics are, you may need to wash them multiple times.
• Clean kitchenware and washable toys in a dishwasher. Depending on how polluted the objects are, you may need to wash them multiple times.
• Use diluted vinegar or basic cleaning solutions, such as Simple Green, to wash other objects and surfaces.

Cleaning Unwashable Items: Cleaning wall-to-wall carpets, furniture, upholstery, mattresses, books, and other personal belongings is typically not possible.

• Fabric-based items, such as carpets, furniture, upholstery, and mattresses, that cannot be completely submerged in water and scrubbed with soap will continue to retain thirdhand smoke reservoirs that readmit toxic pollutions.
• Items that cannot get wet, such as books and magazines, will continue to retain thirdhand smoke reservoirs that readmit toxic pollutions.
• These objects need to be replaced.  Even professional deep cleaning methods often fail to remove tobacco smoke residue that has penetrated into upholstery or into carpet padding.

Cleaning Structural Surfaces: Removing thirdhand smoke from structural elements, such as walls, floors, ceilings, doors, cabinets, HVAC units, airducts, and wall insultation is difficult and expensive, especially if there is a lot of thirdhand smoke in the home.

• If you hire a professional (e.g., painters, remediation experts), they typically use Trisodium Phosphate (TSP) to clean surfaces around the home. TSP is a hazardous chemical, and it requires specialized tools and personal protective equipment. TSP cannot remove thirdhand smoke residue embedded in porous materials like wood panels, particle board, and drywall.
• Alcohol-based primers and paint may trap thirdhand smoke residue on a wall. It may remove the tobacco odor (at least temporarily), but it does not remove thirdhand smoke chemicals. 
• Ozone generators remove tobacco odors from the air by changing odorant into odorless compounds. Ozone generators create new chemicals and do not remove chemicals embedded in materials. 
• Masking tobacco odors with fragrances also does not remove the chemicals.  It simply covers up unpleasant smells.
• In homes where smoking has taken place over many months or years, thirdhand smoke chemicals can soak into surfaces and become embedded in walls, flooring, carpets, and HVAC systems. Once the chemicals are embedded, cleaning the surface is not enough– the residue will resurface and re-emit back into the air. You must remove all of the thirdhand smoke, even what has soaked into surfaces in your home. 
• If thirdhand smoke is embedded in building materials, the only way to guarantee the residue is gone is to completely remodel by removing and replacing all walls, flooring, air ducts, etc.

Do you have more questions about the toxic legacy of tobacco smoke, how it affects human health, and what we can do about it? Learn more here.

Updated: January 2025

Sources:

Ask This Old House. Understanding Thirdhand Smoke. Home Safety Videos. Retrieved from: https://www.thisoldhouse.com/home-safety/21249597/understanding-thirdhand-smoke

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