The term ‘material-‘ or ‘mechanical’ recycling refers to a mechanical treatment process in which the basic chemical structure of the polymer is preserved. The plastic waste is sorted, subjected to intensive physical cleaning to remove potential impurities, shredded and then re-melted or compounded into new material. By contrast, with chemical recycling (also called tertiary or raw material recycling), the polymer is chemically degraded into low molecular weight compounds, purified and then polymerized again. The umbrella term ‘material recycling’ combines both mechanical and raw material recycling. The mechanical recycling process for plastic packaging can include the following steps for rigid packaging systems.