Step 1. Rinse the shirt with cold water from a sink or hose. You should have rinsed the tie-dye shirt after the initial dyeing, but if it was not, it needs to be rinsed with cold water to remove excess dye. Step 2. Fill a tub or basin with clean, warm water to set the remaining dye so that it will not bleed. Mix in a small amount of laundry detergent. Place the tie-dyed shirt into the tub or basin, and let it soak for 10 to 15 minutes undisturbed. Wash the shirt gently with your hands.