To clean the screen of a Dell laptop, shut down the laptop, and disconnect its power supply. Spray the laptop screen with canned compressed air to get rid of dirt that can scratch the screen.
Use a soft, dry cotton cloth to wipe the screen in one direction gently to remove marks. If the screen is still dirty, spray a clean cloth with an liquid crystal display cleaner or a 50/50 solution of isopropyl alcohol and distilled water, and wipe the screen in gentle, steady strokes from top to bottom. If any marks remain, repeat the cleaning process. Wait for the screen to dry before closing the laptop lid or using the computer.