Millions of people are exposed to secondhand smoke every day. People living in multi unit housing are some of the most exposed. The only way to fully protect people from secondhand smoke at Do electronic cigarettes create thirdhand chemical residue? Thirdhand Smoke Resource Center What is the yellow stuff dripping down walls? How to Clean Nicotine Residue Off Walls and Eliminate Smoke Odor How to Get Rid of Nicotine Stains on Walls: 12 Steps