Abstract. Several museum objects made of brass sheets that date by the 19th century were studied during the conservation treatment at the metal department of the State Research Institute for Conservation. All the objects contained cracks, breaks and metal losses that occurred during storage. Samples were taken from the areas with cracks and studied using the methods of X-ray fluorescence analysis, metallography and microhardness measurement. It is assumed that destruction processes were caused by corrosion cracking, which was initiated by the shortcomings of the manufacturing technology of brass sheet products made by deformation in the XIX century.