For your baby's first few weeks of life, you really just need to use warm water to rinse and clean his delicate skin. After that, you may want to use a mild cleanser when he gets particularly dirty. Read baby-wash labels carefully, many contain the foaming agent sodium laurel sulfate, which can be damaging to your baby's immune system. Instead, look for products that use coconut, or other plant-based cleansers, as these natural ingredients will be safer for baby's skin.