Special heat-resistant plastic (polypropylene) labeled as suitable for microwave ovens is also suitable. Such plastic must have one of 3 markings:
horizontal waves – a schematic representation of a microwave (alternatively, there may be the inscription microwave oven safe).
Alternatively, you can use porcelain, ceramics and heat-resistant cardboard (but only for low-fat foods https://greenelly.com/). The main thing is that the material is safe and does not conduct electricity. We hope our readers went to school and remember which material is a conductor and which is a dielectric.