Pour 3 cups of bleach into the washing machine, and fill the machine the rest of the way with hot water.
Close the washing machine lid and allow the machine to run for a minute to allow the bleach and water to blend together well.
Place the light blue clothing into the washing machine and run another minute or two of the cycle to thoroughly coat the clothing.
Stop the machine and allow it to sit for about 15 minutes, giving the bleach time to work on the blue dye in your clothing.
Finish the cycle as normal and repeat the process if any of the color remains.