Strip all brass buying down to one decisive question: what metal will touch my food?
Good sellers answer with nouns. "Pure tin — kalai — applied molten, re-tinnable when worn." Specifics arrive unprompted: who applies it, when renewal's due, what worn lining looks like. Confidence comes from having answered daily for years.
Evasive sellers answer with adjectives: "fully coated," "traditional safe finish," "food-grade quality assured." Notice what's absent — a material name. Coating language especially signals sprayed-on something rather than bonded tin, because kalai needs no euphemisms.
Why this question towers over others: the lining IS the food-contact surface. Every meal negotiates with it. Body metal matters for longevity; lining metal matters for tonight. A gorgeous vessel over dubious lining is jewellery serving dinner.
Follow-ups worth having ready: Is it pure tin, no lead? Can you re-tin when it wears? What does wear look like? — Each has a crisp correct answer. Sellers fumbling all three have told you everything, loudly.
Ask early, ask plainly, buy accordingly.
Customer asking a seller about a vessel interior, seller pointing to silver lining.