David, its a rugbadger ad. What they are saying is if you just hwe a rug, dry it, turn it over and run a vacuum cleaner with a beater bar over it, you will have a pile of dirt.
Of course you will. Doesn't mean to say the rug isn't visually clean and satisfying to the customer.
Same as cleaning a carpet, do you think you can get all the dirt out, I doubt it. You are carrying out a cleaning operation which will only remove a percentage of the dirt but will present a visual improvement.