An aqueous composition comprising chitosan and fibroin nanoparticles, with a diameter equal or lower than 140 nm, and an acid agent, with pH equal or lower than 6, and viscosity equal or lower than 3.5 kg×m−1×s−1 measured at 25.0±0.1° C., kit and method for finishing and/or preservation and/or restoration and/or renovation and/or repairing and/or consolidation of manufactures, in particular ancient manufactures are disclosed.