Tobacco residue

In detail

Tobacco smoke deposits a mixture of tars and nicotine as a thin, sticky, yellow-brown film on every surface in a room, including the ones nobody cleans — ceilings, the tops of doors, the inside of lampshades, the back of a television. Because it arrives as an aerosol rather than as a spill, it coats uniformly, which is exactly why it is hard to see until a picture is taken down. The film is oily, slightly acidic and water-repellent, so plain water beads off it and a light wipe redistributes rather than removes. The carpet institute separates the two forms in its database: tobacco itself, the dry material, opens with vacuuming and is a particulate problem, while smoke routes to the solvent branch — solvent, warm water, ammonia — because the deposit is a tar. Alkaline cleaning is what generally works on hard surfaces, since alkali saponifies the oily fraction. The odour half of the problem is separate and more stubborn, because it is being re-emitted continuously by film in porous materials, and repainting over it without sealing simply moves the source behind the paint.

Why

• Tobacco residue is explained by Adsorption of odour molecules
• Tobacco residue is explained by Solubility and polarity