A CRT's glass face may be coated, and LCD faces are plastic, so they can be delicate. Clean first with a dry microfiber cloth. (A monitor-cleaning brush works for dust.) For persistent grime use a microfiber cloth dampened with water, followed by a dry one. Avoid ammonia-based cleaners such as Windex. Antistatic wipes can help with CRT displays, though today's CRTs have much less static than those sold a decade ago. Vacuum the vents to remove dust; don't use compressed gas to blow dust in.

Be wary of display-cleaner sprays and wipes. Some are not safe for certain monitors, but unfortunately manufacturers don't give model-specific cleaning instructions.