Can a white coating on glasses really be removed? That depends on three things.

3. Prevention and dishwasher settings
   Even if you remove the deposits, they will reappear on the next wash cycle without adjusting the washing conditions:

Water hardness and salt: Check the water hardness and dose the regeneration salt in the dishwasher accordingly.
Temperature and programme: Wash glasses on a gentle programme (ideally up to 50 °C). High temperatures damage glass.

Rinse aid: Helps to drain water from glasses and thus prevents the formation of limescale.