On the outside : Bar Keepers Friend powder or a strong solution of warm water and Soda Crystals, hosed off and buffed up with a microfibre cloth.
Bar Keepers Friend is great, you can feel it digging in and lifting all kinds of dirt off the screen but it won't scratch or damage the surface.
On the inside, any supermarket glass cleaner that contains vinegar and buffed up with a microfibre cloth.