Thanks to Krissy for this Frugal baby Tip!
I saw this not to long ago. Just put 15-20 drops of tea tree oil on a washcloth and throw the washer in with the dipers, when I tried it I was amazed at how new it made my diapers look and how bright they were. Not to mention the slight smell issue I'd been battling and the "stain" I had fought with on a diap for weeks were gone!
You can get cheap Tea tree oil from Wal-mart (off brand but doesn't matter) in the first aid aisle. I've also seen that a mama uses the tea tree flavored cooking stuff & it works she says.