What can I use to clean the display?

The manufacturer recommends a dry, microfiber or lint-free cloth, and to add an LCD cleaning solution onto the cloth for the more stubborn marks. If you don't have solution, use a water in a spray bottle to moisten the cloth. The point is to not let water have a chance of seeping between anything, especially while it is powered on. Do not use alcohol based cleaners or abrasive chemicals.