The types of impurity found in raw cotton are:
- Seed: this is the largest type of impurity found in raw cotton. It may consist of un-ginned seeds, with fibres still attached, ginned seeds or under-developed seeds and part of the seed.
- Chaff: A collection of vegetable fragments, most of them consisting of leaf, bract, and stalk. A bract is a form of small leaf growing beneath the cotton ball.
- Dirt: Sand and soil which originates from the cotton field.
- Trash: The term trash is often applied to the combination of all the above impurities.