A loose term embracing, in its widest sense, the non-fibrous foreign matter present in bales of raw cotton other than abnormal items, such as stone, timber, pieces of old iron, etc.
Note 1: Normal whole seeds, either ginned or un-ginned, are frequently excluded from this category but broken portions of them and also whole or broken undeveloped seeds are usually regarded as trash.
Note2, The main component of trash is chaff and dirt in the form of soil or sand.
Foreign fibres such as lengths of sisal, jute, hemp, and grass are sometimes regarded as trash but usually receive special reference when easily recognizable.
Textile Resource (http://www.textile.org.uk)