Most newborn parents would think that just using a bit of hot water and washing liquid will do the job of cleaning out the bottles, however it doesn't get rid of the ground that is left behind from milk protein and also any pulp or juice residues. If you were to not remove these from the bottles your baby could end up with an upset tummy. This cleanser is made out of natural ingredients and specific enzymes that act upon the milk protein and so on. Because of the mild formula it makes it perfectly safe for babies. This solution is PH neutral and should be used in conjunction with warm water. 100% BPA free.