A suctionable gel for eliminating a contaminating species contained in an organic layer on the surface of a material, consisting of a colloidal solution comprising, preferably consisting of: 1 wt % to 25 wt %, preferably 5 wt % to 20 wt % based on the total weight of the gel, of at least one inorganic viscosifying agent; 13 wt % to 99 wt %, preferably 80 wt % to 95 wt % based on the total weight of the gel, of an organic solvent selected among the terpenes and the mixtures thereof; optionally, 0.01 wt % to 10 wt %, based on the total weight of the gel, of at least one dye and/or pigment; optionally 0.1 wt % to 2 wt %, based on the total weight of the gel, of at least one surfactant. The disclosure further relates to a decontamination method using the gel.