The permanent exhibition “Treasures of Portuguese Archaeology” of the Portuguese National Archaeological Museum is composed mainly of gold and silver artefacts which present extensive surface corrosion. The construction of the exhibition room dates from the late 1980s, and it was conceived with the highest security standards in mind. However, at that time, the importance of the choice of compatible materials and equipments for the exhibition of metal artefacts was still unknown, and the same was true for the influence in terms of corrosion development, even for gold objects, if an inappropriate material was selected. Preventive conservation directives and actions have been developed since then, and presently one is confronted with new paradigms for the exhibition and preservation of artefacts, and, moreover, of cultural heritage. A preventive conservation project, which is currently in its initial stages, was set up with the objective of identifying and understanding the pathologies observed, in order to correct the problems presented by the exhibition room. This article presents an overall view of the project, a description of the alterations observed, and a summary of the methods proposed for obtaining responses to the respective problems, with the purpose of correcting the room’s fragilities.