Oliy scalp and face can be due to over sebum production from the sebaceous glands. These sebaceous glands are present in abundance at face and scalp. Over production of androgen or over sensitivity of the receptors of the androgen on the sebaceous glands can cause increased sebum production leading to oily face and hairs. Hot and humid environment and inheritance can also cause this condition. For oily scalp, special shampoos are available while for oily face you can apply mild cleanser before going to bed and after waking up.