This paper deals with the problem of the appearance of some types of salts that most often occur in ceramic bodies and methods that are performed to protect against the deterioration of such material. The analyses are performed on three ceramic tiles on which the presence of salt is not visible to the eye. Given the proximity of where the tiles were located, they are presumed to be contaminated with salts. This process, invisible to the human eye, cannot be confirmed otherwise, unless tests have been performed that can confirm it. As test items, three Azulejos facade tiles were taken that were an integral part of the architectural heritage of the 18th century in Lisbon, Portugal. A different method of salt presence determination was applied to each of the three items, suitable for the different types of salts present in the item. Salts in ceramics represent a problem that can potentially permanently degrade the structure of ceramics. For this reason, it is extremely important to stop the process of damage caused by salts, in order to preserve the object and its value permanently.