Yes, you can microwave aluminum bowls. However, there are some risks associated with doing so. Aluminum is a good conductor of heat, which can cause food to cook unevenly. In addition, aluminum can reflect microwaves, which can cause sparks and fires. For these reasons, it is important to use caution when microwaving aluminum bowls. Ensure to cook food evenly and avoid placing the bowl too close to the microwave's metal walls.