The ancient artform of bidri is a process by which the soil is mixed with ammonium chloride and water to produce a very specialk paste which is rubbed onto the heated bidri article. The paste dakens the body of the piece but has no effect on the silver inlay, As the paste is rinsed off, the design springs dramatically into view, the shining silver replendant against the black surface, Finally, opil is rubbed on the piece to deepen the black matt coating.
With proper maintenance, Bidri items can be kept bright and beautiful indefinitely. Use silver polish to shine the silver inlay, then rub pure vegetable oil over the entire surface. Water will not harm bidri, but soap and salt should be avoided as they can spot the thin black surface.