Yes, you can microwave aluminum foil tray. However, there are a few things to keep in mind. First, make sure that the tray is not touching the sides or bottom of the microwave. Second, only use foil trays that are labeled as “microwave safe”. Third, use caution when removing the tray from the microwave, as it will be hot. Finally, avoid using foil trays with sharp edges, as they can damage the interior of your microwave.