Each day in my Carpet Cleaning Baltimore, Md business I visit homes to access their carpet cleaning needs. Often, in multi-level homes with a second story there usually seems to be black lines around the edges of the baseboard walls. I am often asked what these dark lines are called and where they come from?
These lines are called filtration lines. They are usually gray or black and caused by an improperly balanced ventilation system. Timely changing the heating filters can keep these lines from becoming a problem.
Another part of maintaining your heating system is cleaning your vents from time to time. Here is a great article that explains How to Clean Household Air Vents.
Even a professional carpet cleaner with specialized cleanings skills may not be able to remove the stains 100%. The problem that I have seen when homeowners try to correct these types of stains themselves end up damaging their baseboards.
Before cleaning these areas, please contact a professional carpet cleaner. Hope this information is helpful.