An oily skin type is exactly what it sounds like – excess oil on the face produces a persistently shiny or greasy appearance. If you don’t treat your oily skin, pores can become clogged and enlarged, and dead skin cells may accumulate. Blackheads, pimples and other types of acne are also common with this skin type. Sebaceous glands are located within the skin and are responsible for secreting an oily substance called sebum. Sebum lubricates the skin, protecting it from drying out or becoming irritated. This oil, along with sweat, is secreted through the pores. When this process goes smoothly, sebum not only lubricates your skin, but it also removes dead skin cells and other irritants from your pores. However, when over-active sebaceous glands produce excess sebum, your skin looks shiny and your pores can become clogged, leading to a host of skin imperfections.