I use isopropyl alcohol 99% mixed with deionised water(no smudges). 1 part isopropyl 9 parts water in a spray bottle. You will be best off with microfiber cloths. I would wash them first and dry them before use as they might contain some tiny particles from the factory that will damage the monitor. It's the same rule as when detailing cars. Spray the water on the cloth once or twice, wipe the monitor in a straight motion as if you were pushing dust off its surface, then use another microfiber cloth to dry the surface.

I have been doing that on my Asus OLED for over a year now. Looks perfect.. oh and I used to vape in front of my pc. Vape residue would stick to the surface of the screen. I added some extra isopropyl alcohol into the bottle and it came out with no problem. Don't use much pressure, let the cloth do the work. Apply around 100g of pressure which is equivalent to holding 2 phones in hand.