In a bar, glasses and dishes are constantly being washed. A bartender will often make a cold cocktail, but find that the only clean glasses are those hot from the dishwasher. Instead of panicking, there is an effortless trick that most bartenders use — and I do at home — hold the hot glass under cold running water. The cold water will quickly change the temperature of the glass. Once the glass has cooled in your hands, dry, and pour your cocktail.