I "benefit" from recovering a lot of aluminum and copper scrap from my profession in home exteriors. I trade a LOT of it for wheelweights at my local scrapyard. They really don't care what I'm using it for. Suppose I could have the "cash" instead but the trade-scrap is never in short supply and I do make a living for what I do already... so if I'm getting 2-for-1 for bail-able aluminum on wheelweights, which worked out to $0.48/lb for the WW last trip, it's all relative to me.
That said, carefully sort stick-ons from clip-ons. And from there carefully sort lead clip-ons from zinc or zinc-alloy clip-ons. You do NOT want zinc in your alloy or you'll have a hell of a time filling out a mold or getting consistent weights/accuracy.
Using a Lee hardness tester, which seems pretty reliable to me testing it with a few "known" hardnesses... I'm getting around 11 BHN on the ingots air-cooled. I water-drop my bullets out of the mold and consistently get 14-15 BHN. There IS plenty of antimony in them - having tested several runs by oven-annealing, I've gotten 25 BHN easily (550F for 20 mins, pre-size, lube after) playing around. Not one to push lead to high velocity, and not seeing any benefit to shattering bullets, I tend to use them either air-cooled at 11 or water-quenched at ~15ish.
FWIW