20. The heating element
In addition to the basket of your air fryer, there can also be dirt on the heating element. To clean this, first make sure that your air fryer is turned off and has cooled down well. With a soft microfiber cloth you can wipe any grease from the heating element. Note: in this case do not wet the cloth. This will prevent any water damage.
Source: KookFans, Katies Kottage, Dutch Ovens Cookware, Reddit| Images: iStock, Pexels