What are some tips for maintaining a dive mask?

To clean smudges and oily residue from the lens, apply a small dab of gel toothpaste and gently rub, followed by rinsing in tap water and air drying.  After diving, rinse the mask in freshwater only and allow the mask to air dry out of direct sunlight.  To store, wrap loosely in a soft cotton cloth and place in a protective box or bag out of reach.  To avoid scratches, never place the lens part of the mask down on a surface.