Don Foreman wrote:

CerroSafe was developed specifically because it is safe for kids to
handle, as in casting toy soldiers.

No, it's not. It's 37.7 % lead and 8.5% cadmium, worse actually than
CerroBend.

The "safe" refers presumably to slight initial shrinkage allowing a
duplication casting to be removed without cracking the part you are
using as a mold, allegedly it then expands back to the original
dimension.

The plain tin/bismuth alloys (example CerroTrue) would be less toxic,
but the lowest melting point there is 281 F, so you can't use the water
bath and as a result have to be carefull not to overheat.