Preventing those black lines along the edges of your carpeting ....... They are called soil filtration and will usually appear if you live in a major city like Boston or if you live in the suburbs and have a garage under or even sometimes an oil-fired heating system. It's soot that is drawn into the interior wall cavities of your home due to negative air pressure and exits out of the wall cavities where the wall meets the floor, depositing the soot in the carpet fibers which are acting as a filter. You can prevent this from happening by simply applying a bead of caulking that seems to seal off any airflow before installing a wall-to-wall carpet. It's not expensive, only takes about 15 minutes to do an average size room but will keep the rugs looking much nicer for years. I would love to see all interior designers follow this simple procedure. It's just that little extra step. Your clients would appreciate it. As always, if you have any questions about this or any other problem, please call Alec at 781-871-4428 or contact me by e-mail at Alec@Alecscarpetandupholsterycleaning.com