Diagnosis
Grease aerosolizes during air frying and sticks to the upper heating element and the enamel surface around it.
How to Fix It
Unplug and cool the oven. Fill the drip tray with hot water and a squirt of dish soap. Run the oven on Bake at 350°F for 20 minutes. The steam will soften the deposits. Once cool, use a non-abrasive scrubbing pad on the ceiling. Avoid touching the quartz heating elements directly.
If That Didn't Work
For stubborn carbonized grease, use a dedicated oven cleaner labeled safe for enamel surfaces. Apply only to the soiled enamel, not the elements or electronics. Follow the product's instructions precisely.
Heads Up
Never use abrasive powders or steel wool on the interior enamel. You will scratch it, making future cleaning harder and potentially damaging the surface.