[en] A drying colloidal gel has been developed to clean contaminated surfaces in order to reduce the volume of radioactive effluents. This gel makes the stage of surface rinsing useless, only an aspiration through a vacuum cleaner is necessary. This technique generates a few grams of solid effluents per square meter of decontaminated area and has been adapted to stainless steel surface. Further developments will concern the surface decontamination of porous materials and of the inside lining of complex duct systems through the use of gels and foams. (A.C.)