The cleansing foam is also designed to draw in dirt dust and harmful fibers for example powder within a dry cleaning method totally. Some companies use a foam which they spray on the rugs. http://nhomag.com/adredirect.asp?url=http%3A%2F%2Fbookmarklayer.com%2Fstory17979603%2Fcarpet-cleaning-tips-to-get-those-spots-out-%EC%9E%90%EC%9C%A0%EA%B2%8C%EC%8B%9C%ED%8C%90-ml