Recycling is a fundamental process within materials science and engineering aimed at reducing waste by converting discarded products and materials into reusable raw commodities. This technological stream involves the systematic collection, sorting, and processing of materials, including polymers, metals, glass, and fibers, which are then subjected to mechanical or chemical treatment. The objective is to purify and reform these waste streams into industrial inputs, thereby lessening the demand for newly mined or extracted virgin resources. The practice contributes to resource conservation and energy efficiency by creating a circular material economy.