im planning to use my gonna expired ebm for milkbath to treat baby's irritated dryskin and ezcema , anyone could teach me how to put for the ratio between water and ebm? and if ebm got to be heated up first before mixing together with warm water in the tub?

One of my friends simply used whatever amount of "expired" breast milk she has, thaw them and add warm water to the necessary amount for the baby's bath. Don't think there really is a standard ratio. Hope it helps your baby's skin! Heard that breast milk is very moisturizing. :)