Follow the steps below:

• Dilute isopropyl alcohol (not rubbing alcohol, as it may contain oil) into a solution of no greater than 50% alcohol and 50% with distilled water/deionized water. Purified/bottled water works well too. A 50/50 mix of white vinegar and distilled water is also effective.
• Put the solution in a small atomizer bottle, the type that you push from the top to get a fine mist. Don’t use this, however, to spray on the screen itself.
• Apply the solution to a cotton cloth, such as an old T-shirt, lint-free microfiber cloth, or some other very soft cloth. A large cloth is best, since it will help to reduce the risk of leaving streaks across the screen from finger pressure.
• Wipe the cloth against the screen in a circular, or other consistent motion. Rapid circular movements generally eliminate streaks. Apply an even pressure to the cloth but take care not to press your fingers into the cloth or screen.

Note: The information above is from the following web site:

http://www.wikihow.com/Clean-a-Laptop-Screen-with-Household-Products