Furnaces

The eyes of the skull suddenly began to glimmer and to glow like red coals, and wherever the three turned or ran the eyes followed them, growing larger and brighter till they flamed like two furnaces, and hotter and hotter till the merchant's wife and her two wicked daughters took fire and were burned to ashes. Only Vasilissa the Beautiful was not touched.

Sims removes the batteries and crunches the phones to bits, then melts the shards and rubble in furnaces. What comes out is an amalgam of metals—plus slag from the plastic and glass and impurities.