The ability of this coating to repel oil will diminish over time with normal use, and rubbing the screen with an abrasive material will further diminish its effect and may scratch the glass. in such above techniquies are maintain so your iPhone Safe and Clean.
Clean your iPhone immediately if it comes into contact with anything that might cause stains or other damage – for example, dirt or sand, ink, makeup, soap, detergent, acids or acidic foods, or lotions. Follow these guidelines for cleaning: