I use a 25% solution of 99% Isopropyl alcohol with 75% water. Use ONLY a soft cloth and lightly dampen it with the cleaning solution. Do NOT use any paper product of any kind, and don't allow the cleaning solution to get behind the bezel of the LCD.
I've cleaned dozens of them this way without any damage. However, heed the cautions about letting the solution get behind the bezel, that can render the display inoperative. And if you search here, you'll find out what happens if you use something like a paper towel, it scratches the surface, and there's no fix for that.
Do not use the 70% Isopropyl alcohol, it contains oils and other ingredients.