Using these Jimmy's SmartStix Interchangeable Needles is a breeze. First, pick the right needle tip size (they're available from US 2.5 - 11) for your project. Then pair it with the appropriate Jimmy's Smart Cord. When you're knitting, you can use the 1 - inch markings on the needle tips to measure your work as you go. To measure your gauge or do wraps per inch, just lay your knitting against the marked needle tip. As for care, since they're made of aluminum, a gentle wipe with a dry cloth after use is enough to keep them clean. Avoid using harsh chemicals or abrasive materials as they might damage the color - coding and markings. Store them in a dry place to prevent rusting. If you have a whole set, keep the needles and cords organized to make it easier to find the size you need next time.