IMHO, you should keep your fine silver and sterling leftovers
separate. They can both be melt down and re-used but why add more
fine silver to the sterling? It’ll change the balance. I keep jars
of all my leftovers separate. All labeled: Sterling, Fine, Argentium,
Copper, Base (silver plate, nickel, parawire and other unknowns),
Aluminum and Anodized Aluminum.