I work for Ingram Roofing Inc. in Troy, MI. I have seen bays affected by the muriatic acid wash bricklayers use. I have used the wadding polish Nevr Dull to clean copper patina off to a higher then original luster. It requires alot of buffing to remove the patina and should be clear coated immediately if you want to keep it shiny. I recommend Revere Copper products Incralac acrylic laquer. It will clear coat your bay for about 5 years. Both products will not harm your brickwork.