No, it is generally not recommended to microwave ceramic mugs with metallic elements, such as metal handles, even if they do not touch the sides of the microwave when inside. The reason is that microwaves can induce electric currents in metal, which can lead to arcing or sparks, potentially causing damage to the microwave or the mug and posing a safety risk.
While the metallic handle may not touch the sides of the microwave, the microwaves can still interact with the metal and create a concentrated electric field around it. This can result in arcing between the metal and the surrounding environment, including the ceramic glaze or any nearby objects.
To ensure microwave safety, it is best to use microwave-safe materials, such as microwave-safe ceramics without any metallic elements. Look for mugs labeled as microwave-safe, which indicates that they are designed to withstand the specific conditions of microwave heating without causing any harm or risks.
If you are unsure about the microwave safety of a specific mug, it's best to refer to the manufacturer's instructions or choose an alternative microwave-safe container for heating your beverages or food.