Abstract: An apparatus for cleaning those parts of processing machines of synthetic materials on which synthetic residues adhere includes a container which receives the parts and is airtightly closable. This container is associated to a heating unit which heats a liquid carrier medium to a temperature above the melting point of the synthetic residues adhering to the parts to be cleaned therefrom. The container is tiltable around a horizontal axis between a horizontal charging position and a vertical operating position. Connected to the container is a tank which is located below the container when the apparatus is in the horizontal position, and which accommodates the heat carrier medium. Upon movement of the container and the tank from the horizontal position into the vertical position, the heat carrier medium flows into the container and upon reverse movement flows back into the tank. An overflow determines the maximum filling level of the heat carrier medium in the container.