Found this info at various laundry websites:
Spice up the colors in your laundry by shaking a few teaspoons of black pepper into each load. Don’t worry about flakes of pepper dotting your clothes. The pepper will wash out during the rinse cycle.
Black Pepper: adding some teaspoons of black pepper into each load to your laundry could keep the colors of your clothes. Do not worry about pepper dotting your clothes as it will wash out through the rinse cycle. - See more at: http://www.pouted.com/4-natural-mate....5ZMduZwC.dpuf