Soluble salts are one of the most important factors of deterioration of cultural heritage, being desalination by different methods the most common intervention to minimize their harmful effects. Presented in this article are the results of an evaluation of the effectiveness of two desalination methods: immersion baths and application of poultices, combined with the use of ferrocyanides as salt crystallization modifiers. The evaluation has been conducted using two different granites, and the efficacy of the methods to desalinate samples contaminated with a pure solution (NaCl) and a complex solution (sea water) has been analyzed. The results indicate that, in certain cases, the use of modifiers makes the methods of desalination evaluated more effective. It is found that the effectiveness of these products depends mainly on three factors: the mechanism that controls the desalination process applied, the ions present inside the samples to be desalinated, and the porous system of the stones.