The purpose of this report is to illustrate how and when this method should be used for the consolidation in mural paintings. The basic methodology is described (materials, times, and methods of application). Two combined operations (cleaning, based on ammonium carbonate, and consolidation based on barium hydroxide), can interact to create new chemical components with results appropriate for the conservation of mural paintings. Variations in the application of this method are illustrated, according to the support, painting techniques, and degradation. The most appropriate weather conditions for efficient results are indicated. A critical analysis on the behavior of this operation over a period of several years is made with respect to other techniques of consolidation. All the phases of the operation as well as various examples carried out on specific paintings in the last years, are shown through photographic documentation. See also AATA 19-1595 and 21-2092 for related studies.