I didn’t use Neocate but soy formula also leaves those yellowish stains. I think regular milk formula does too, but to a lesser degree. I always fought these stains by spraying them heavily with Shout immediately. I’m a bit of a perfectionist when it comes to laundry and my children’s clothes, so I change them right away if they stain something. Soaking also works wonders. If you don’t want to soak then keeping the stained area wet until you launder really helps. So, I spray the garment immediately with lots of Shout, and then later on wet it with water or spray it again so it does not dry. Most of the times this works for me.