The other day, I had lunch in a Thai restaurant in Tokyo. The menu items were good, but what impressed me more was the other thing; it was rather a hot spring day and an iced tea was served in a metal cup. We usually have something cold with a glass or ceramic cup. I think it's rare to use metal cup. Actually I have no metal cup except for a camping gear. I think it is because a metal cup is not suitable to have hot drinks because it becomes too hot. It is not good either to drink something cold because it easily forms dew on its surface and wet table. However, it is very pleasant to have cold drink with a metal cup on a hot day because the cool metal feeling on your lips will make you feel way cooler than a glass or a ceramic cup. The cup in the Thai restaurant had a saucer to avoid dews and I could fully enjoy the benefit of the metal cup. How about the idea to make a ceramic cup with a metal part? -- Whole part is made of ceramic except the area lips touch so that it has the cool metal feeling with no dews.