Back To The Family Handyman
From 
Del.icio.us
Digg
Reddit
Facebook
StumbleUpon
TwitThis
About This Project
Q The light-colored carpeting in our home has developed a black residue along the baseboards. We had the carpets cleaned, but it didn’t get these black lines out. Help!
Jessie Hollinder, Bloomington, IL
A The most likely cause of this common and irritating problem is a small draft or airflow under the baseboard, wall or floor. The air in our homes contains small amounts of dust, oils and other suspended particles. As the air flows under the baseboard, the carpet filters out some of this debris, leaving the dark line. The dirt is particularly troublesome because it consists of tiny particles (particularly soot) that adhere tightly to the carpet fibers, and it’s usually out of reach of the vacuum.
You can often prevent future black lines by reducing airborne soot, that is, your use of candles; wood fires; unvented gas, oil or kerosene heaters; and gas stoves without range hoods. A malfunctioning gas- or oil-burning furnace or water heater can also dump soot inside your home. Be sure to have your combustion appliances serviced regularly to avoid potential soot problems.
Other solutions are more difficult. You can call in a heating/cooling specialist to better balance the supply and return ducts to your rooms. In an unbalanced room, the supply (incoming) air can pressurize the room and force air out through whatever cracks are available. (Sometimes this results in a dirt line under the door!)
You can also pull up the edge of the carpet and caulk the crack or gap under the baseboard. This doesn’t always work because the gaps are often difficult to get at and seal well. The best time to do this is when you’re installing new carpeting.
In most cases, professional cleaners can remove the dark line. However, be sure to hire one who understands the problem and knows how to get the dirt out.
Advertisement 
