Many times people will have their carpet cleaned, everything looks great, but over time old spots seem to reappear….the stain comes back. In the carpet industry, this is known as re-soiling. This happens when a cleaning product is used on an area and cleaning residue remains behind. A cleaner’s job is to grab dirt and cleaner residue does just that – it grabs dirt off your shoes, your pet’s paws, anything it contacts. Therefore, over time, cleaned areas slowly re-soil and the old stain spots return. All Healthier Home Carpet Cleaners contain Tetraflex™, a proprietary polymer system that embrittles as it dries. This means any residue left behind after blotting dries completely and is vacuumed away – no residue left behind to grab dirt and re-soil.