2 parts distilled water, 1 part alcohol with a microfiber towel/wipe. Depending on location, just using tap water may due some harm due to the minerals.
I guess you could be paranoid of the disolved salts and iron in your tap water, along with the bleach (chlorine) they have sanitized it with, but it sure seems to do just fine. Again, alcohol and windex and all the other recommended chemicals are rather caustic and tend to dissolve things. Including plastic and other materials if used in high enough concentrations and left applied for long enough.