Yes I've found it's very frustrating looking for "genuinely zero lead" brass and bronze. Almost all scrap has lead in it to some degree, and even new metal often has a trace.
Neat, this dovetails with another interest of mine, pottery. NaF is "sodium feldspar" and Ca-Si compounds are "wollastonite" among others. Both useful as fluxes in metal casting, in addition to their pottery uses.
I'm not sure it's brass anymore without the lead.
Why does it seem that the better a material works the worse it is for humans.