Breastfed baby poop is water soluble. You do not need to remove breastfeed baby poop before washing. Around 4-6 months of age, many babies start solids through cereal. At this point, stools transition to a thicker "peanut butter" consistency. For best results, this should be removed (as much as possible) from your diapers prior to washing. Formula fed and older babies typically have firmer stools. This should also be removed from your diapers prior to washing.