What should be done after using Nitrox before switching to breathing air?

After using Nitrox, it is essential to flush the tanks and regulators to remove any residual enriched air before switching back to breathing air. This process helps ensure safety and equipment integrity. Nitrox, typically a mix of nitrogen and oxygen with a higher concentration of oxygen than found in regular air, can lead to risks such as oxygen toxicity if the equipment is not adequately prepared for the different gas composition. Flushing the equipment helps eliminate any traces of the enriched air mix, allowing for a fresh and safe transition back to standard air use.

The other options do not adequately address the primary concern of ensuring that the equipment is free of residual Nitrox before transitioning back to breathing air, which is critical in maintaining safe diving practices.