whenever someone brings something to our store with worn off black rodium, we’ll do the regular clean/check/polish and then just use an industrial black marker to fill it in. we don’t charge for it, and it’ll actually last a long time if it doesn’t see heavy wear!
the alternative is spending at least $400 for something you’ll use like 4 times a year. PLUS you’ll have to charge for it, and no one wants to pay for a full rhodium just to replace what is most likely a single tiny accent of their jewelry hahahah
keep at it with the repair work, that’s the lifeblood of a good jewelry store. people like the store they bought their trendy new ring at, but they LOVE the store that made their old ring new again.