It is a coating put on metal that makes it look like plastic. It can be used for other stuff as well. like mouse cords for your computer
- coating with another metal - paint coating - plastic coating
For insulation.
like plastic handles on pliers a plastic coat over stuff
insulator
thermo plastics
Because plastic is Not Metal and the penny is.
Plastic is 2 and 5 and the coatings do not matter.
optical dish
usually plastic, sometimes metal or have rubber coating
because melamine is fire resistant
so they do not burn themselves quickly
Hair grips can be made with either plastic or metal. Some of them have plastic coating over the top of the metal.