Product Description Synthrapol is a mild soap specifically made for removing excess dye so that dried articles may be washed with other laundry. When dyeing not all of the dye will react with the fiber being dyed. Excess dye, therefore, must be removed to prevent backstaining. Rinse the fiber as thoroughly as possible with a small amount of Synthrapol, then launder with one tablespoon per load. Synthapol suspends and carries the excess dye from the fiber.