Composition leather under 411510 must have a base of leather or leather fiber — it is made from ground or shredded genuine leather bonded into sheet form. Artificial leather (e.g., PVC- or polyurethane-coated fabric) has a textile or plastic base and is classified in the plastics or textiles chapters. The key test is whether the base material is leather fiber or a synthetic substrate.

Leather dust and powder recovered from buffing and finishing operations are used as fillers in composition leather production, as soil amendments in agriculture (for their nitrogen content), and as raw material for glue and gelatin manufacturing. Leather flour — a finely milled form — also finds use as a binder in certain industrial applications. These by-products are traded internationally as industrial inputs rather than consumer goods.