Using your Bosch T123X100 jig saw blades is a breeze. First, make sure your jigsaw is turned off and unplugged. Then, insert the T - shank of the blade into the blade holder of your jigsaw until it clicks into place. When cutting, start at a slow speed and gradually increase it as you get into the material. These blades are great for a variety of materials like metals, plastics, and fiberglass, but be careful with different thicknesses. For thicker materials, use a slower speed and more pressure. As for maintenance, after each use, wipe the blades clean with a dry cloth to remove any debris. Store them in a dry place to prevent rusting. If you notice the blade isn't cutting as well as it used to, it might be time to replace it. Also, always wear safety goggles and gloves when using these blades to protect yourself from any flying debris.