I would try to throw everything into the molten lead in a low, wide crucible, about 500C (wood fire) is enough to remove the gilding (or small pieces of gold) in a few minutes, and steel doesn't form a solution with lead at all (solubility ~0). In a kilogram of molten lead, many tens of kilograms of your jewelry can be processed. There shouldn't be micro losses because no liquation of gold during rapid cooling (when extracting cleared hot metal bases from a mass of lead with a slotted spoon). Work under a hood with a filter, although at temperatures up to 800C, there is almost no lead vapor. After you can make cupellation in a magnesia or cement cupel or dissolve the lead-gold alloy in nitric acid. If gold was soldered with silver to steel, it will also be quickly removed by the lead.