I have a niello ring made in Russia. About 60% of the black
"niello" has fallen/chipped out. I was inquiring how/where might I
go to find someone who can remove the remaining niello and replace
it either with the same or with colored enamel. I was once told
that a high frequency ultrasonic cleaning might cause the remaining
"niello" to fall out. Also, I was asking that when/if I get the
remaining niello removed, where might I go to get it replaced
(re-nielloed) or enameled.
Perhaps you can help?