Is it a bowl? Is it a mug? Either way, itâ€™s the perfect vessel for coffee, cereal, tea, and to show some U of T pride. In striking black and yellow, this is the perfect gift! Microwave safe. While our ceramic mugs are dishwasher safe, washing by hand is the best way to care for your mug. The high temperatures and harsh detergents used in a dishwasher can cause designs to fade, and pewter decorations to loosen over time.