That new cherry-red shirt you just purchased is fantastic, but just think how faded the colour will look after the shirt has been washed a few times. Add a teaspoon of pepper to the wash load. Pepper keeps bright colours bright and prevents them from running too.
Not a bad deal, and certainly a good form of insurance if you tend to forget to set your washer to cold (like me).
5 Peculiar Uses for Pepper [Reader’s Digest]