Alkaline molybdenum cation and phosphonate-containing cleaning composition

A treatment system for treating metal substrates, comprising:

• a) an aqueous alkaline composition comprising:
• a molybdenum cation;
• a phosphonate;
• and
• an alkaline component;
• wherein the pH of the aqueous alkaline composition is at least 11, and the aqueous alkaline composition includes no more than 50 ppm of phosphate based on a total weight of the composition;
• and
• b) a pretreatment composition for treating at least a portion of the substrate, comprising a Group IVB metal cation.

A treatment system for treating metal substrates, comprising:

• a) an aqueous alkaline composition comprising:
• a molybdenum cation;
• a phosphonate;
• and
• an alkaline component;
• wherein the pH of the aqueous alkaline composition is at least 11, and the aqueous alkaline composition includes no more than 50 ppm of phosphate based on a total weight of the composition;
• b) optionally, an activating rinse for treating at least a portion of a substrate;
• and
• c) a pretreatment composition for treating at least a portion of the substrate, comprising a metal phosphate.