dirty coffee cup after operating with microwave oven, heating water in microwave can be dangerous,

dirty coffee cup operating microwave oven heating water can be dangerous appliance aroma background beverage blow boiling point cafe caffeine cappuccino container cooking drink electric energy espresso experiment explode exploding grunge heat homemade hot kitchen light liquid mess messy molecule mug open phenomenon porcelain radiation safety splash stain superheat warm warning wet image shot ultra wide angle lens