Quick Tips – Do not Use These Products to Clean Your iPhone (Or You Wish You Did not Have It) ~ Macs Tech Notes
All iPhones get fingerprints and it's too easy to get the iPhone dirty with ink, lotion , makeup, dirt, food and oil. If you're facing an iPhone that needs cleaning, resist the desire to spray it with window wash, rub alcohol or ammonia, or worse, scrub it with soda or Borax.
That's because all iPhones have oleophobic -oil repellent coatings on the glass surfaces that make it easy to dry out of fingerprints. You will not remove that coating any faster than it will wear off normally, and cleaning products will strip it quickly. Instead, Apple recommends a soft, lint-free cloth that you will use for glasses or camera lenses. You can even save over $ 18 and get a 6-pack from Amazon for less than $ 6 here.
By the way, although the iPhone 7 and newer have some dust and water resistance, it's important to avoid moisture in the openings-most of the time, a lens cloth should be all you need.