We found some novel synthesis routes for alkali-metal molybdenum bronzes. The synthesis techniques are composed of simple hydrothermal treatments of mixed-valence compounds (or mixtures) with ACl or ACl+AOH aqueous solutions (A=alkali metal). Using these routes blue bronze (K0.30MoO3) and red bronze (K0.33MoO3) were obtained from hydrogen molybdenum bronze HXMoO3 or HXMoO3 + MoO3 even at 410 K.