Like any piece of clothing, and especially undergarments, bras can become stained or yellowed over time. They can also be whitened in a number of ways so that they regain the original bright, attractive look they had when you first purchased them.
What to Use to Whiten Bras
Woolite and Bleach
Wash yellowed or stained bras in Woolite and a splash of bleach to bring out the white in the fabric. If there are specific stains on the bra itself, then spray them with stain remover and wash the bra normally before using the Woolite-and-bleach combination. It's best to use non-chlorine bleach if you can, as it will be better for the fabric and your skin when you wear the bra.
Oxyclean has been known to whiten old bras back to their original white. By soaking bras in a solution of OxyClean and water for a few hours straight, stains or discoloring will be quickly removed. The solution of OxyClean to water should be 30 percent OxyClean to 70 percent water. Then run the bras through a wash cycle. When they dry, the bras should have regained most of their original white color.
Soak and Bleach
By soaking stained bras in cold water mixed with liquid detergent for half an hour, stains and discoloration will be loosened. You can then launder them in a cold-water cycle mixed with a large amount of non-chlorine bleach. Most of these stains will be removed and be replaced with the original white of the bra's fabric. If certain stains can't be removed, try heavy-duty stain removers and repeat the process. The bra can only get whiter through this process.