computed tomography Decision making In preparing the strategy of a metals conservation project, an interdisciplinary approach is essential. This implies the participation and close collaboration between as many experts as is possible. At minimum, the curator (archaeologist, historian, or art historian), a scientist specialized in the corrosion of metallic objects of cultural heritage, and the conservator or restorer should be involved in the project. Documentation Systematic and well-managed documentation is an essential prerequisite for quality conservation and restoration treatment as "it is no longer considered acceptable to undertake a conservation treatment without recording the object and the intervention." Conservation documentation should include the state of the object's condition before, during, and after treatment. Any technique used to assess the object's condition should be documented as well. Conservation "documentation can also be viewed as a 'surrogate object', and can therefore form part of preventive conservation strategies intended to enhance access to information while reducing the handling of objects." Although documentation requirements differ across institutions, most records follow the same general format, including: Object data, such as location, ownership, and accession records Progress data, such as the date the object was received for treatment and when treatment is completed Technical data, such as examination results and analysis Object condition and treatment data, including materials and equipment used in treatment Recommendations, such as advice for storage and display or reexamination and further care of the object References, photographs, and diagrams Ethics and ethical problems in metals conservation The ethical concept of conservation of metal objects in principle is the same as those in other fields of conservation-restoration of cultural heritage. However, there are several specific problems that can only be found in the conservation of metals; problems of heat treatment of archaeological objects, and the problem of radical restoration of historic, technical, and architectonic objects too. While the first case problem is primarily in the destruction of valuable scientific data, the problems in the case of technical, architectural, and historical objects are that radically restored items only simulate the original appearance of the object, thus that object can be considered more or less fake, which only superficially simulate long-lost or the never existing state of an object. Whenever possible the preservation of real historical substance is preferred. Ethical problems connected with conservation of sacred metallic heritage objects can be included too. Preventive conservation Preventive conservation, also known as collections care or risk management,