Using these spare lenses is easy. First, carefully remove the old lenses from your Madison Code Breaker II sunglasses. Then, align the new lenses and gently insert them into the frame until they fit snugly. When wearing the sunglasses, make sure they sit comfortably on your nose and ears. As for maintenance, clean the lenses regularly with a microfiber cloth and a mild lens cleaner. Avoid using harsh chemicals or abrasive materials as they can scratch the lenses. Store your sunglasses in a protective case when not in use to prevent damage. Also, be aware that while the lenses are impact - resistant, try to avoid dropping or subjecting them to strong impacts. If you have any issues with the lenses, refer to the limited lifetime warranty for assistance.