We always prefer hand washing out glasses, using lukewarm water. Most of our glassware is not dishwasher safe due to its composition, by cleaning it manually it stays beautiful for longer. Limescale particles in your dishwasher cause erosion, which results in dull scratches. That would be a shame, right? If you still want to wash it in a dishwasher, add descaler and a glass protector and set it on a gentle program.