This comes up often. The only real rule is don't use any chemicals.
A high quality microfiber cloth ( the kind that feels slightly prickly ) is the singular way to go.
How to Clean my Screen!
I bought a 10$ screen cloth that was useless. Later I bought a 2$ microfiber cloth that worked like a dream!
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I usually use my 3M microfiber cloth, BUT i do get some nasty marks from my 3.5 year old daughter and so i use this cyberclean product it's like a slimy putty. really great. check their site CyberClean: home
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