Using these Metabo Speed - Flex 36 Grinding Wheels is easy. First, make sure your grinding machine has a 7/8 arbor to fit the wheels properly. When starting, hold the tool firmly and gently apply the wheel to the surface you're working on. These wheels are great for a variety of materials like steel and stainless steel. Just move the wheel steadily across the surface for the best results. Remember, these wheels work fast, so don't press too hard. This can help reduce noise and dust during operation. As for maintenance, keep the wheels dry and store them in a cool place. Check the wheels regularly for any signs of damage. If you notice any cracks or chips, replace the wheel immediately. Since it's a package of 25, you'll have plenty on hand for your projects.