Wax for molding
Since the wax is molten, they have some sulphur in a spoon or crucible and pour it in the molten wax. And with the sulphur going to the bottom or staying on top, it stays where it is and mixes only its substance in the wax, and renders it more meltable when warming it, in such a way that having molded it, the wax gently melts in the mold like butter, without leaving any blister or boil. Also be warned to not give it too much heat.
at left top margin of folio 109r