The article discusses the barium hydroxide and the silicon ester techniques which had previously been concluded ineffective for stone consolidation. More recent investigations and the availability of modern techniques of analysis and testing have shown that they have merit under the proper conditions. The author maintains barium hydroxide in solution is both safe and effective when applied to an appropriate stone (calcareous), and employing an appropriate technique. Similarly, silicon ester applied to siliceous materials such as sandstone, marl, adobe can yield good results for some years.