A new method of Mo+ ion beam production is presented in the paper. The method bases on the chemical sputtering/etching of the molybdenum parts (e.g. anode) of the arc discharge ion source by the chloride containing plasma. A mixture of CCl4 (or CHCl3) vapor and air was used as the feeding substance. The separated Mo + beam current of approximately 18 µA was achieved. The measurements of the ion current dependences on the discharge and lament currents as well as on the magnetic eld ux density from the electromagnet surrounding the discharge chamber were performed in order to nd the optimal working parameters of the ion source.