तीक्ष्णताम्रसंस्कारं च बुध्येत ॥ कZ_०२.१३.५८ ॥
tīkṣṇatāmrasaṃskāraṃ ca budhyeta
One should also recognize (diagnose) the processing/treatment involving sharp/caustic agents and copper (tāmra-saṃskāra), i.e., signs of copper-based alteration.
The state must staff or train assayers with technical competence, not merely rely on market reputation.