I have time to time taken customers’ jewelry and melted it down,
rolled it out and made new jewelry with it. However, I had one case
where no matter how carefully I melted the gold, it was very cracky,
so I sent it in for scrap in exchange for clean gold wire.
When I reuse silver scrap, I make sure there is no solder. I cut it
allout, grind it out, every speck of solder gone before I melt down
all the clean silver scrap into ingots so I can roll it out. Been
doing that for 8 years on a regular basis when the price of silver
and gold shyrocketed and business was bad. Just being able to reuse
my old silver and making my own wire kept me going.
As for gold, I get conflicting info. Some say I can melt down old
gold jewelry with solder. Some says I have to have clean gold scrap,
no solder. I’ve done both. I can say the gold with solder is more
prone to cracking, esp. white gold which can be a B with an Itch. I
use my judgement now when I’m confronted with mystery gold.