Abstract: It is disclosed a process for cleaning vehicles, especially cars, with an alkaline washing composition, preferably comprising one or more surfactants, where the washing composition is sprayed onto the vehicle with one or more nozzles or foam generators and where the alkaline washing composition in connection with the spraying onto the vehicle is combined with an aqueous solution of a cellulose derivative forming a semi-stable composition with congeals and absorbs/adsorbs the dirt particles removing them from the surface when the composition is rinsed off. It is preferred to add fibers in the rinsing water when hosing the composition off or in the cleaning solutions, and it is also preferred to perform the process at a pressure, e.g. 1-150 bars. The two components forming the cleaning composition are preferably combined by using an ejector system operated with water for obtaining the relevant concentrations of each component.