Abstract: The invention relates to a device in the form of a washing machine for cleaning machine parts that are soiled with oil or fat. Said washing machine comprises a housing that can be closed with a lid and that houses a basket for receiving the soiled parts. A spray nozzle system supplied with especially hot cleaning liquid is disposed inside the housing and acts upon the parts to be cleaned that are stored in the basket. For conditioning the cleaning liquid, the device interacts with a bioreactor. The invention is characterized in that the cleaning liquid circulates in a closed circuit between the device and the bioreactor via a discharge line and a supply line. Inside the discharge line means are provided for regulating the temperature of the cleaning liquid for the bioreactor.