I doubt they hired a guy to sit there and sort the WW... really, have you ever sorted a 5 gallon of WW? It takes like an hour, I don't even do it anymore, I just throw a bunch of stuff over the fire and scoop anything that doesn't melt when lead has melted.
And on most zinc weights, you have no way to know they are zinc other than they float when the lead has melted.
50% of zn weights I can sort because they are bright and have ZN or Z on them, and 50% get in my mix and I scoop them out.
Clips weight alot. I bet you 20% of the weight at least is scrap.
Buy 100 pounds, smelt it, and weight the scrap...
I am always between 30-40%.
Just letting you know, do whatever you want and then report with the weights.
Unless the scrap guy had too much free time, I bet you it's bs and they didnt sort them. are you kidding me, imagine the tons of WW that they would have to sort 1 by 1 ?