Do not use chlorine bleach on baby clothing. It worsens the problem and irritates their skin.
Hydrogen peroxide removes baby formula from shirts and clothing as well as the yellowing in christening gowns. Mix a fifty-fifty solution of a 3% peroxide (found in drug and grocery stores) and water. Soak the clothes for 30 minutes and launder as normal. Air dry to make certain the stain is completely removed. Heat sets a stain. If after soaking for 30 minutes the stain has not been completely removed pour the peroxide directly onto the stain. Soak another 30 minutes then launder as normal in cold water.