Its charge is frequently cited as the reason the clay should never, ever come into contact with metal of any kind, lest the clay be rendered useless or harmful. (humblebeeandme.com)
A second mistake is using metal stirring utensils as contact with metal will kill the mother of the whole thing. (talesofakitchen.com)
It also doesn't require direct contact with the metal, which can help maintain the machine. (geekwrapped.com)