Fill up your washing machine with hot water. Add 4 oz. (half a bottle) of liquid fabric acid dye to the hot water.
Soak the shirt that you will be wearing on your solo flight in hot water. Place the shirt into the washing machine.
Allow the shirt to dye for the entire length of the washing machine cycle.
Remove the shirt from the washing machine when the cycle is complete. Rinse the shirt under cool water to remove any excess dye and to prevent the shirt from bleeding. Dry the shirt as normal.
Wear the shirt during your first solo flight.
Cut the shirt tails, or the entire back of the shirt, with a sharp pair scissors. Typically, this part of the tradition is done by either your instructor or the other students in your program.
Write your name and the date of your solo flight on the shirt in permanent marker. Pin the shirt on the wall where the other shirt tails are located.