Actually, I contaminated 10lb of pure lead with 2 ounces of zinc. Then "fluxed" the zinc back out with copper sulphate powder in small batches many times. The blue cs dries out to white crust on the alloy and then I crush it up and mix it into the lead. It turns brown as the copper is leeched from the cs and it bonds the zinc to the powder. Then scoop it off and do it again. Keep doing that until the powder stays white. Then all the zinc is gone and replaced with an equivalent amount of copper. I then pour that out into 1lb ingots to be added to 10lb of clip on wheel weight lead. If you do it with wheel weight lead, the cs will start replacing the tin too, that turns the white stuff grey. If you're not comfortable contaminating your lead with zinc, you can do it with tin as well. It's just tin is way more expensive than zinc. When you're done, you can add tin back in to help fillout. The copper makes the alloy very slightly harder, but more importantly, very tough and malleable. Water quenched clip on wheel weight boolits crack and break when mashed with a hammer but with the copper, they hold together and mash flat without cracking crumbling or breaking.