My b has "dandruff" after birth, like skin flaking. After a few weeks, I took him to a paediatrician who prescribed a special shampoo for him which he had to continue to use for half a year until the "dandruff" was gone.
Actually, it is a common skin infection among new born babies, not dandruff.
頭泥is brown in colour and can be removed by applying baby oil and then rinse.