When you arrive at a friend's place and you might find that their home is well cared for. The wood floors shine and there is no trace of dust or stains that tarnish the beauty of the floor.
But how does one assess the cleanliness of carpets that cover the floors of your business or office space? If you do not notice any spots, you will probably conclude that they are clean. Do not be fooled, this is just an appearance. People, without even realizing it, carry a lot of dirt with their boots and their shoes.