First, by not touching it!
Anything will do but at first, just try some water on a soft cloth. Water, the universal solvent.........just don't let any liquid drip down the display & get under the bezel, there are electronics down there!
If that doesn't remove the finger oils then try some Windex on a soft cloth. Don't worry about wrecking the display, I've literally cleaned hundreds of monitors over the years & haven't screwed-up one yet!