Post-consumer waste in a clothing and textile context is clothing or textiles that have been used and discarded which may then be used for recycling or up cycling.
Pre-consumer waste is the waste created during the production of garments. This can include manufacturing scrap such as offcuts, misprints, damaged finished garments etcetera. According to Rissanen (2012) 'on average, clothes that are created by cutting and sewing fabric use approximately 85 per cent of the fabric produced to make them, meaning that 15 per cent of it is wasted.' http://textiletoolbox.com/research-writing/design-minimise-waste/