What must you do before storing an open fluid container?

Before storing an open fluid container, it is essential to seal it properly. Sealing the container helps in preventing contamination and minimizes the risk of spillage or leaks. It also protects the fluid from environmental factors such as dust, moisture, and temperature changes, which can affect the integrity of the contents.

Moreover, sealing fluids can help maintain their chemical stability and prevent any volatile substances from evaporating into the air, which is particularly crucial for hazardous or reactive materials. Proper sealing practices are a critical aspect of safety and compliance with proper storage regulations.

While emptying the container might seem like a viable option, it is not always practical or necessary, particularly if the fluid is still needed for future use. Likewise, shaking or heating the container may alter the properties of the fluid and could potentially create hazardous situations or degrade the material. Thus, sealing the container is the best practice before storage to ensure safety and product integrity.