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ethyl alcohol and ammonia-based cleaners can yellow your flat-screen or laptop monitor over time. stay away from them and you will be safe ;)

I use water to wipe down and then dry it off. Use a soft shop towel (blue towels located in walmart or auto part stores) they are soft and will not harm your screen.

You can also buy a kit if you want for cleaning lcd screens, but its a waste of money so your better off with water and a soft towel.
 
i use iklear, I put a few sprays on the cloth it comes with and wipe in a circle motion...
(i do this so that the solution doesn't get in the edge of the screen....
I guess you put the screen flat on a table, and hold the computer part up...)
 
Hot water and a towel ended up working. Feels like I have a new computer. It was getting really bad there for a little bit. All the small water spots made it hard to read small numbers.
 
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