There are three categories of paper that can be used as feedstocks for making recycled paper: mill broke, pre-consumer waste, and
post-consumer waste.
Mill broke is paper trimmings and other paper scrap from the manufacture of paper, and is recycled internally in a
paper mill.
Pre-consumer waste is material which left the paper mill but was discarded before it was ready for consumer use.
Post-consumer waste is material discarded after consumer use, such as old corrugated containers (OCC), old magazines, and newspapers. Paper suitable for recycling is called "scrap paper", often used to produce
molded pulp packaging. The industrial process of removing
printing ink from paperfibers of recycled paper to make
deinked pulp is called
deinking, an invention of the German jurist
Justus Claproth.