The decision to melt is up to you, if it is already hallmarked I would be inclined to leave it as such to save on an assay, you may be able to find a dealer willing to ping them with xrf if you do melt if you build a buying relationship with them they may provide it at no cost, but do not expect to just roll up and ask them to complete xrf on your goods if no such relationship exists, the business will possibly want to know in advance if you are intent on presenting with bars to scan. Regarding purification by smelting, I would not bother, the fuel required plus reducing agents and length of burn time necessary to remove and oxidise is prohibitive for a refining step in my opinion. Chemical recovery and refining is the only way to go and if you are getting your scrap at a decent price why would you bother, just flip it or stack it until you are ready for chemical recovery and refining. I cannot stress enough the dangers of refining and recovery with chemicals and silver, highly unstable explosives can inadvertently be produced, toxic fumes are ever present. Forget everything you have seen on you tube as it does not show the entire process and responsibility of you the individual. There are plenty of examples on YouTube but these should only be used as examples of the reactions involved in recovery and refining NOT as tutorials. You have furnaces and everything accompanying their safe use ,glassware, the right and wrong gear, cleaning of glassware is not even looked at and is a must for correct uncontaminated reactions and real refining. Filtering systems,Chemical use and purchase plus any local restrictions if you are suburban. Then chemical waste and correct disposal and neutralisation, fume hoods and the list goes on. I am a member of a refining forum I can refer to you when you are ready, be warned the members of which do not take kindly to Joe Imbecile using some glass jars and analytical grade reagents in his laundry or bathroom. You must research the topic and show you are willing to do it the RIGHT way. Some books you need for research first: C.W. Ammen- recovery and refining of precious metals; C.M Hoke- refining precious metal wastes. Read each book a minimum of 3 times before proceeding any further. I can also refer you to some cd productions that detail particular processes and cover silver in full.