1. Liquids and other foods must not be heated in sealed containers such as lids or nipples, since the contents inside can expand as they warm up, resulting in explosion or rupture;
2. When heating liquid foods, use wide-mouth containers and leave enough space between the food and the container's rim to prevent boiling over;
3. Microwave heating of beverages can result in delayed eruptive boiling, therefore care must be taken when handling the container;
4. Before heating round-shaped foods like potatoes, chestnuts, and sausages, pierce them with a knife or fork to prevent bursting or splattering;
5. Eggs in their shell and whole hard-boiled eggs should not be heated in microwave ovens since they can explode, even after microwave heating has ended.