Our breast-fed son occasionally has poops that are greenish. These tend to stain his clothe diapers. What is the best way to get stains out without compromising the ability of the diaper to do its job? I remember hearing somewhere that you shouldn't bleach diapers, although I don't remember the reason.
Bleach is really harsh on cloth diapers and sure your diapers will be "germ free" but bleach can really hinder the absorbency of the fibers because it can degrade them.
The most common and effective way people try to remove the stains from cloth diapers is sunning them to dry. The sun acts as a natural bleach. That site talks about adding lemon juice, hydrogen peroxide, and vinegar to your laundry cycle. If you have a really a sunny day coming up, I'd try the sun first.
Sunning the diapers is certainly the best (and most natural) method, but that does assume that you will have decent enough weather.
When the weather doesn't allow for sunning, we add a small amount of OxiClean Free to our wash cycle. This helps to whiten the diapers and doesn't leave a residue.
The best method that seems to work for me is to soak the poopy clothes in hot water and 1/2 scoop Vanish stain remover. After that I just put it in Washing Machine with 2 caps of Dettol (disinfectant) and without adding any detergent. The hot water seems to take away the stains very fast. The hot water does the trick most of the time even without the stain remover, but I add it when it is quite dirty.