If you do not want to pay for a commercial product, mixing up your own solution is very easy. If you don’t want to take any chances use a professional product.
Two ingredients you will need.
70% Isopropyl Alcohol
The recipe is easy: Mix the Isopropyl alcohol and distilled water in equal parts (50/50) inside an empty Windex-like bottle. Do not use tap water! Doing so will leave white smears on your screen after cleaning it up because of the dissolved minerals inside the water.
Next, you will need to find a good, soft piece of microfiber cloth to clean your display. Avoid paper tissues at all cost! Using those on your screen would be just like scrubbing sandpaper on it and may scratch it permanently.
Start by turning off your screen. Dampen your piece of soft cloth with your cleaning mixture and then wipe the display gently from top to bottom. Never spray liquid directly onto the LCD. When you’re done, wait a few minutes to let your screen dry, and then you can turn it on.