White clothing is especially hard to keep clean, as the bright white color is not forgiving when it comes to residue, stains or wear that leaves a garment looking dull over time. Bras lose their bright white color quickly as body oils, lotions and perspiration are in direct contact with the fabric. And the clothing worn on top can sometimes rub color onto the white bra. Although bleach is one way to whiten bras, bleach is a harsh chemical that can cause breakouts on sensitive skin. There are natural whitening agents that will work just as well.
Turn your washing machine onto a delicate wash cycle using warm water. Add your normal laundry detergent. Warm water will assist in removing any loose residue that is causing the dull color.
Pour either 1 cup of lemon juice into the washing machine or 1 cup of white vinegar. Both will work equally to whiten the bras. If you prefer, mix the ingredients by adding 1/2 cup of each. The lemon juice will naturally whiten plus add a lemon-fresh scent to the laundry cycle. The vinegar works well for a dulled bra that also contains odor, as the vinegar is a natural deodorizer and disinfectant that will remove foul smells and bacteria.
Pour 1/2 cup of baking soda into the washing machine as well, which is another natural whitening agent as well as a deodorizer that will remove any odor caused by perspiration.
Hang dry the bras outdoors in direct sunlight. The sun will natural whiten the bras. If sun drying is not possible, place the bras in a tumble dry setting in the dryer, or hang dry indoors.