Finally a way to test to see if a carpet is polyester tester / olefin vs nylon. Why is this so important? because polyester/olefin need specialized chemistry to break the oil bond. With this tester just add a couple drops to a fiber. If its nylon it will dissolve in seconds. If its polyester or olefin it won't dissolve. It's that easy. And dont forget, TMF makes the only presprays with polyester cleaners built in. So now any synthetic fiber is no challenge for TMF and professional cleaners!