The surface of brass (Cu80/Zn20) exposed in water and different aqueous solutions and 2-mercaptobenzothiazole (MBT) is studied by XPS. The leaching of zinc (dezincification) is observed in pure water and in borate solutions. On the contrary, if brass is exposed in 0.5M NaCl or Na 2 SO 4 solutions copper is removed from the surface layer leaving brass surface covered by oxidized zinc, thus “decuprification” occurs. Exposure of brass in 0.05mmol/lMBT solution reduces results oxide growth and forms mix complex CuZnMBT layer, which thickness increases with time. Adding 0.5M NaCl to this solution does not remove copper from the surface.