Open side down. I come from a "restaurant" family. Glasses and cups are stored upside down as to avoid collecting dust and pollutants. You won't pass inspection if the upen ends are placed up.
Down. Our glasses and mugs that we use for daily living are in the kitchen cabinet with the opening down. Our crystal stemware in the dining room hutch is up. I will wash it before using.
We live in the dry, dusty Southwest so dust is an ongoing battle in our homes.
