Question: what does it mean when you scratch your head and white stuff comes out?
Answer: The “waxy” sebum is what people often refer to as “scalp gunk”. It forms as a white, dandruff-like coating of the scalp. Most people seem to discover this when they unconsciously scratch their scalp and find a white, waxy layer under their nails. ... A gland that release sebum is called a sebaceous gland.