Fabric protector is a clear substance that we can optionally apply to carpet after cleaning. It makes carpet more resistant to certain kinds of soiling. Effectiveness varies by product and type of soiling.
We charge extra for applying it, but if you expect your carpet to become heavily soiled, fabric protector is well worth the investment. Here is one carpet cleaner’s test of the effectiveness of two brands, compared to no protector other than whatever was applied at the carpet factory. Here is an ad for the product that we currently use. It’s a flourochemical, like Teflon, except formulated for fabrics. It works best against everyday soiling and makes vacuuming more effective.