My mom, sister, and dad were chain smokers living in a house where the carpet didn't get vacuumed much. I never let anybody smoke in my room but my walls were still yellow, as was anything else white. The cig smoke gave the dust a sticky property to it making it even harder to get the dust off small areas. It was originally why I went to using the vac with the thick long bristle brush on my PC. Next to washing components it was the closest things I could get to clean.