The bottoms are narrow enough and handles high enough that they fit into most car consoles and baby stroller cup holders. You drink out of the three small holes and pour your drink into the large hole. The cork, once there is warm liquid inside, expands and settles into the hole. After removing the cork, they are microwave and dishwasher safe (except for the 18k gold ones - they don't go into the microwave as they have metal). As with all pottery, the more you expose it to high temperatures the more quickly it will wear. If the cork gets dirty you can wash with warm water and soap and then rub coconut oil or an oil that you use on your cutting boards to make them water repellent again.