The invention relates to a method of cleaning the surface of a material that is coated with an organic substance. The inventive method is characterized in that it comprises the following steps, consisting in: introducing the material into a treatment chamber, having a pressure of between 10 mbar and 1 bar therein, which is supplied with a gas stream containing at least 90 volume percent of oxygen; and generating a plasma by passing an electric discharge between the surface of the material and a dielectric-covered electrode in order to break down the organic substance under the action of the free radicals O thus produces. The invention also relates to an installation that is used to carry out said method.