Final answer:
When using a jigsaw or any machinery with a blade, safety is paramount. You must ensure the blade has come to a complete stop before removing it from the cut to prevent injuries.
Step-by-step explanation:
When using a jigsaw, it is important to wait until the blade has come to a complete stop before removing it from the cut. This safety measure prevents potential injuries from a moving blade and ensures that you can handle the equipment without the risk of being cut. The reference to jagged pieces, chemicals, and machinery operation touches on the broader topic of safe practices when working with machines. In this case, ensuring the blade has stopped is a fundamental aspect of safe machine operation.