When doing laundry, we've been conditioned to separate dark colors from whites. But when it comes to treating your white laundry, be sure to understand that not all white garments are the same. When it comes to any garment that is not 100 percent cotton -- including polyester, spandex or nylon blends -- even if it's blended with cotton, these pieces need to be separated. Synthetic-blend white pieces won't brighten with the addition of bleach. In fact, they actually turn yellow. Instead, wash them in cold water and add white vinegar, which has a natural acid to help neutralize odors and brighten whites.