FiberGard will go through the coating and penetrate the fabric fibers, for an enhanced level of protection. In fact, many mill-applied or ordinary spray on treatments are only temporary measures. FiberGard should be reapplied on average about every 4 years or when repellent diminishes.
Effectiveness depends on the nature of the staining agent, and of the weave and type of the fiber.
Hot coffee, acids, bleaches, and dyes are particularly tough. During application, you'll notice a faint solvent smell. Once it dries, fabrics are odorless. And, they look, feel, and breathe the same as before. However, you must remember not to over-saturate, and to let fabrics dry out of direct sunlight, or yellowing may occur.