Microwave. hi,i've got a problem i was reheating my meal last night but it got burned and i can't

Question

hi,i've got a problem i was reheating my meal last night but it got burned and i can't remove the burned stains inside my microwave can you pls help me!now everytime i use my microwave the burned smell comming out!pls help is there anything i could do to clean this?microwave is stil working and i don't want to buy a new one.pls help..thanks a lot