Sweepings — fine dusts and residues collected from jewelry workshops, refinery floors, or industrial facilities — typically contain a blend of platinum, palladium, gold, and silver that cannot be attributed predominantly to platinum. They are classified under the separate 'precious metal scrap NES' heading to reflect their mixed composition. Misclassifying sweepings as platinum scrap can result in incorrect duty treatment and valuation disputes, since the payable metal mix differs significantly.

Refiners typically require a sampling and assay report confirming platinum, palladium, and rhodium content; a certificate of origin or chain-of-custody declaration; and evidence that the material is genuine spent catalyst rather than new or off-spec catalyst (which would be classified differently). Some refiners also require a declaration that the material has not been adulterated or diluted, as fraud involving artificially reduced PGM content is a known risk in the secondary catalyst market.