There is a spot tin on the silver coin. It is soldered before with a ring and used like clothes button. I heated it and try to remove the tin with a chips of wood but didnt achievable. What is your suggestion? Thanks
Wow...looks like a real problem. Is this a silver coin? Looks like it. You might try heating it with a micro torch while you hold it with something and then tap it when the solder liquefies...brrrrrrr...wait for better advice.
I would try using a soldering iron and a desoldering wick. https://www.amazon.com/Vastar-Desol...&sr=1-2-spons&keywords=desoldering+wick&psc=1
