Long Story Short: Buy a cleaning kit made exclusively to clean the screen on your smartphone. Smartphones are not cheap and the last thing you want to do is ruin the screen on your phone. You will see various DIY mixtures, but I have found it is best to get a product that is already packaged in a spray bottle that often comes packaged with a lint-free microfibre cloth. You will not regret it and you will find you will be cleaning and sanitizing your phone more often. Always spray the solution on the cloth and not directly on your phone or other devices.
What you don’t want to do: Due to the special coating on many of these smartphones, do not use household cleaners such as window cleaners, aerosol spray cleaners, solvents of any kind, bleach, ammonia, undiluted alcohol, or hydrogen peroxide.
Where to buy: If you look on Amazon (click here) you will find an array of products made exclusively to clean smartphones. The one that I specifically selected is the WHOOSH! Screen Cleaner Kit. The cleaner is designed to clean eyeglasses, smartphone, laptops, tablets, HDTV’s, and wearable tech, such as smartwatches. The kit is reasonably priced and ships with a large and small (portable) container of the cleaner with Two 6′ x 6′ cloths + BONUS Poo cloth.