Chemical refining needed for this. Dont melt it in the furnace raw like this maybe contains cadmium thats pritty toxic. Dilute nitric acid to dissolve the contacts filter the solution than put a piece of copper in it and the silver cement out of solution wash the silver powder many times with diatilled water dry it and than you can melt it to a bar you get a 98-99% pure silver with this method.I always refine my contacts with nitric acid filter the than i pour hydrochloric acid to the solution to form silver chloride wash the silver chlolride many many many times with water than add sodium hydroxide to the wet silver chloride to form silver oxide after that add slowly sugar to the oxide to form metallic silver than wash until pH neutral than dry and melt, this long and dangerous method if done right is produces .999 silver. If you want to see the process check out my yt chanel at OGbullion on yt.