Per the wiki article mentioned by Mitch//pa (thanks) -
Pot metal—also known as
monkey metal,
white metal, or
die-cast zinc—is a colloquial term that refers to
alloys of low-melting point metals that manufacturers use to make fast, inexpensive castings. The term "pot metal" came about due to the practice at automobile factories in the early 20th century of gathering up non-ferrous metal scraps from the manufacturing processes and melting them in one pot to form into cast products. A small amount of iron usually made it into the castings, but too much iron raised the melting point, so it was minimized.
There is no metallurgical standard for pot metal. Common metals in pot metal include
zinc,
lead,
copper,
tin,
magnesium,
aluminium,
iron, and toxic
cadmium. The primary advantage of pot metal is that it is quick and easy to cast. Because of its low melting temperature, it requires no sophisticated foundry equipment or specialized molds. Manufacturers sometimes use it to experiment with molds and ideas (e.g.,
prototypes) before casting final products in a higher quality alloy.
Sounds like 'stew' for cars....