On all my displays, plain water and a microfiber.
Or, lens cleaner (one labeled safe for AR and other coatings) and a microfiber. Your Targets/Walgreens/Walmart/CVS/et. al. should have this. Can go fancy and buy the Zeiss version of this. Since I wear glasses, I always have this at home and a small bottle in the car.
I always have a microfiber with me, and have one in the backpack I put the laptop in. Can always buy a small bottle of lens cleaner and put it with the microfiber in the backpack.
No to paper towels, window cleaners, multi-purpose cleaners.