Using your ChiaoGoo End Stoppers is super easy. When you want to switch needle sizes between projects, just screw the end stoppers onto the ends of your ChiaoGoo Twist Red Cables. This way, you can keep your current project in place and use the needle tips for something else. Remember, each size of the end stopper has a different color, so match the white small [S] ones with [S] coded cables, the black large [L] ones with [L] coded cables, and the red mini [M] ones with [M] cables. To keep them in good shape, just store them in a dry place. There's no need for any special cleaning, but if they get dirty, a gentle wipe with a dry cloth will do the trick.