Boiling water in a microwave does not make the microwave dirtier.

In fact if it boils it can help clean it!

True. The mess comes from a son reheating food, often tomato sauce based, without a lid.

most lid are plastics, so i suggest people heating without lids. Cleaning mwave is east anyway. I am sure ppl don't want microplastic laden food.

Better that than reheating it in a kettle!