Just learned this from our Saati pal Keith Perkins

Check out this magical removal of a bad stain on a screen.

Use a sponge of melamine foam and then in the video we used  Saati IR29 though I have been advised  that you can use IR1 to even greater effect apparently. The big brand name version of these sponges is “Magic Eraser” and here you can read what that magic is.

(Squirt, do not mist!) , and scrub gently with the sponge on both sides of the screen, and then rinse.