To use liquid Rit dye, fill a bucket with hot tap water and the dye, thoroughly wet the fabric to be dyed with cool water, place it in the container to soak for 10 to 30 minutes, rinse the fabric thoroughly in a sink, and run it through a washing machine with an old towel to remove excess dye. To dispose of the leftover dye bath, pour the liquid down the drain, and clean the sink immediately to prevent staining.
Alternatively, use liquid Rid dye in a washing machine. Wash the fabric normally before dying it. Next, set the water temperature on the washing machine to the hottest setting. Pour one bottle of liquid Rit dye diluted with hot water into the soap dispenser portion of the machine.
Run the cycle for 10 minutes, and add 1 cup of salt diluted with hot water to the load. This acts as a mordant and sets the dye. After the cycle finishes, wash the fabric again, this time with laundry detergent, and dry the material in the dryer.
Rit dye works best on natural fibers such as cotton, silk, wool and rayon. Polyester blends with less than 40 percent polyester also take Rit Dye. Add a full bottle of dye to the dye bath and soak the fabric longer to achieve a richer, darker color.