That is an old trick and it does work, just as oxygen bleaching works, I guess. You can use green bushes too, apparently, if the grass seems less than perfect. As ours does with a dog and a toddler! Apparently, commons were often covered with laundry! Love, Lucy

I've never tried it as the laundry would probably get trampled by a neighborhood dog LOL

I don't know if the green grass or bushes part is necessary, but hanging things in the sun is definitely a natural bleach. I always try to hang the diapers out on a drying rack (clotheslines prohibited in our neighborhood, and our dog would mess up the diapers if they were just on the grass) and it works WONDERS. I can absolutely tell the days when I have to leave the drying rack inside and the diapers aren't as white. The sun even gets out dark stains from the diapers.

I got a lot of practice hand-washing our clothes on our recent trip to Sudan, and I was amazed at how good the sun is at bleaching white clothes. I never had any green plants around, but I would hang our socks and my husband's t-shirts on the straw walls that they use for privacy screens around their houses. The socks usually ended up looking like I'd put them through the laundry at home with bleach!