Using your favorite laundry detergent is perfectly fine when washing your whites, as long as you follow the care labels. However, most major brands offer a line of special detergent with a non-chlorine bleach alternative that helps keep whites white and is safe for colors. Active enzymes in these detergents are able to remove dirt to maintain whiteness without damaging clothing fibers. In addition, there are non-chlorine bleach alternatives, which are not integrated into the detergent, that can be used as an additive.
Keeping your whites from getting dingy sometimes requires more than just washing detergent. Adding about 1 cup of baking soda along with your detergent will help aid in brightening your clothing. Vinegar will also whiten clothing, in addition to getting rid of residue from detergents. Simply pour up to 1 cup of white vinegar along with your detergent of choice and wash the load as normal. Adding 1 cup of hydrogen peroxide to your laundry will also keep your laundry white.
When whites are already quite dingy, you can still restore them to--or near--their original brightness with a trick that many chefs use. To keep their coats bright white and stain free, chefs add dishwasher detergent to their wash. Add about 1/4 cup of powder dishwasher detergent to your whites and wash them in warm water with your regular detergent. The whitening agent from the dishwasher soap will leave you with clean, bright whites. You can also soak the clothing in lemons or lemon juice and hot water and wash as normal.
Yes, the sun. For those who don't want to add anything to their wash except for laundry detergent, it is possible to keep your whites white using the sun. Either line dry or leave your white laundry out in the sun. Not only will this help brighten your whites, but it will give them a natural fresh scent.