Method of making glass sheets with vehicle pretreatment of refractory

A method of making a glass sheet comprising

• treating a refractory block material comprising at least one multivalent component with a vehicle comprising at least one redox altering component or precursor;
• flowing molten glass over the refractory block material, wherein the treatment of the refractory block material with the vehicle comprising at least one redox altering component or precursor reduces the amount of oxygen production resulting from interaction between the at least one multivalent component and the molten glass, wherein the vehicle comprising at least one redox altering component or precursor comprises at least one alkaline earth compound;
• and the at least one redox altering component or precursor is applied as a liquid and comprises at least 1 gram of redox altering component per every 100 milliliters of liquid.