Detinned steel scrap — where the tin coating has already been chemically removed — is classified as iron or steel scrap, not tin scrap. Tin scrap under this heading refers to material where tin is the commercially recoverable metal of value, such as solder dross, tinplate clippings with significant tin content, or tin-alloy manufacturing residues. The distinction matters because the two categories carry different duty treatments and are directed to entirely different secondary processing industries.

Secondary tin smelters typically specify minimum tin content (often expressed as a percentage of the lot weight) and maximum allowable lead, antimony, and bismuth levels, since these contaminants affect solder and bronze alloy quality. Purchase contracts often include price adjustment clauses tied to assay results at destination, so importers should arrange pre-shipment sampling and analysis to reduce settlement disputes and ensure the material meets the buyer's processing specifications.