It can not be avoided, that here and there arise a few small splashes of fat while using the device. After the fryer had cooled, I wiped with a simple and dry Zewatuch from the control panel to remove the traces of grease. This alone was enough already to simply wipe the applied on the control panel icons and everything is on it printed off.
There was no cleaner or otherwise irfend something used here, only with a dry cloth.
An exact adjustment of the temperature is thus no longer possible.