Fingers spots in smart phone screen make my phone unsecure. Because people can easily draw pattern because of these fingers spots. How can I save my cell phone screen from these fingers spots?
If your phone does not already have oleophobic coating on the screen, the easiest way to fight against fingerprint marks on the screen is to buy oleophobic screen protector.
Olephobic means that there is a thin coating on the screen that repels water, dirt and for your case most important, oil marks.
Also, look at this question that is similar to yours.
Use a stylus, or use the screen with your finger knuckle (the part most people knock on a door with) instead of your finger tip. Finger tips are great at leaving marks because you touch everything else with them and, in most people, they have a lot of sweat glands