Cleaning the screen of a tablet safely My 4 year old son loves my ASUS Eee Transformer, and likes the games and stuff.  But he has a cold, and the screen is literally gross. 

What are safe methods, and conversely what are unsafe methods of cleaning it?

Being a touch pad I am not sure if the surface is specially coated and say, Windex will destroy it.

I understand there might be device specific concerns as different manufacturers may use different screen cover materials that react differently.
You can find special screen cleaning mixtures to use, but they're mostly just alcohol. I've been using a lens-cleaning spray on my phone for years with no adverse effects. Just spray a bit on a piece of paper towel and wipe the screen down. You'll want to use an alcohol based spray, as it evaporates much faster than water, and so won't short out your device.