To give it a try on old stained pads, hang them on a clothes line (or clothes drying rack) in direct sunlight outside, and come back a few hours later to see the natural bleach take effect! If it's not convenient to sun dry pads during your cycle, you can always sun them later to help lessen the stains. Even when the pads are dry, the sun works at diminishing the stains (although some say that the whitening effect of the sun works much better when the fabric is wet). We can't recommend this highly enough! Just try it once and you will be amazed at the results.