Abstract: The method for cleaning the surface of an external wall of a building, includes forming and maintaining a layer of foam of a cleaning agent on the surface of an external wall of a building to detach soil deposited on the surface of the external wall by the cleaning action of the cleaning agent, and subsequently removing the cleaning agent foam from the surface of the external wall by, for example, washing with water. In the method, the scattering of the cleaning agent around the building can be prevented by removing the cleaning agent containing soil as it is, in the state of the foam.

Abstract: A method for cleaning a surface of an external wall of a building includes applying a cleaning fluid containing a strippable film forming agent to the surface of an external wall of a building, drying the applied cleaning fluid to form a strippable film, and stripping the strippable film from the surface of the external wall. Thus, the cleaning fluid which contains soil is removed with the strippable film, so that the scattering of the cleaning fluid around the building can be prevented.