put a cup of water in the microwave for about 5-6 min to get hot and steamy let stand for a few minutes and hopefully it will wipe down nicely.
Brenda is right, that is exactly what I do only I let it stand for about 1/2 hr and everything just wipes off.
try this: https://www.craftylittlegnome.com/the-easiest-way-to-clean-your-microwave/
I agree with the others, except that I like to add some lemon juice to the water. That gives the microwave a fresh clean smell. Wishing you the best.