Final answer:
Metals do not always need to be stored in sealed containers for safety. Highly reactive metals like sodium should be stored in sealed containers filled with oil to prevent their reaction with air or water. However, less reactive metals like silver can be stored in regular containers without the need for sealing.
Step-by-step explanation:
In general, metals should be stored in sealed containers to prevent them from reacting with the surrounding environment. However, not all metals need to be stored in sealed containers for safety. Some metals, such as sodium, are highly reactive and can react violently with air or water. These reactive metals should be stored in containers filled with oil to prevent any contact with air or water. On the other hand, less reactive metals like silver can be stored in regular containers without the need for sealing.