Have you noticed the black lines forming around the edge of your carpet? Especially around radiators, under doors (in particular the airing cupboard) and no matter what you try to do, it doesn't budge?
The black lines are a result of filtration soil. It is pollution that come from underneath your floor and settles on your carpet.
In the cleaning and flooring trade these black lines are referred to as draught marks. Marks that are caused by the movement of air. Air contains pollution and it has the amazing ability to find a way through into your home. The main reason is that hot air rises. Even where the carpet gripper pierces through the carpet backing the air will flow through and form black dots on the surface of the carpet.
So what can be done to stop the black marks around the edge, and sometimes even in the middle of the room?
First of all you will need to try and stop the airflow, with any flooring installation the sub-floor will need to be fit for purpose. One way around this is to lift up the carpet and lay thick sheet of card, overlapping them and sticking them down with tap, and then around the edge of the seal the edge with mastic or caulk. If your sub-floor is made from pine it is better to lay sheets of plastic down and seal the edges. Once you have sealed the floor properly you will then be able to lay your carpet.
So what can be done if the marks are already there?
Once you have addressed the problem of drafts, you can then ask a professional carpet cleaning company to clean the carpets, although 100% removal can not be guaranteed and the marks will return after time.
What Can I do Myself?
Take care - As you will unlikely have the equipment to thoroughly rinse the cleaning solutions you will use out after the cleaning attempts - You can easily make it much worse - It is like washing your hear and not rinsing the soap out - The soapy residue will just attract the dirt and pollution in the air much much faster and before you know it the problem got much worse.