Most commonly the conservation treatment of a gilded object will involve cleaning and consolidation, the purpose being to preserve and prevent deterioration rather than restore. If the object serves a presentational function—such as a gilded picture frame—it may also be important to minimize the visual distraction of damage or loss, so the painting or ceramic displayed remains the main object for the viewer rather than frame or stand. The care and preservation of a historic object, with a full or partial covering of applied gold or metal leaf, should only be undertaken with a clear understanding of the process and materials by which that decoration has been applied (see Gilding, §I.). The leaf itself is extremely thin and fragile, and many of the materials that make up the surface onto which the leaf is applied are soluble in many solvents and so can be easily damaged unintentionally. Any contact with the metal leaf will cause some form of abrasion and loss of original material, and with some metal leaf, such as silver, removal of the protective seal coating is likely to lead to irreversible discoloration by oxidation or similar if not replaced....
The conservation of metals begins with the process of assessing the condition, stability, and losses or alteration that may have occurred to metal objects. Conservators are then in a position to manage risk and take preventative measures to protect the longevity of the material as well as consider a variety of treatments to repair any damage.
See also Metal
Each metal has particular conservation issues related to the metal species or alloy used, how the object was made (cast, beaten, formed, rolled, machined, or extruded), whether or not a decorative finish was applied, and the nature of the environment to which the object was exposed. Condition issues can be identified as being either structural or surface related.
Structural instability can be the result of manufacturing flaws or physical damage. How the object was made can in turn dictate how an object should be treated. For example, a dent in a cast bronze sculpture should not be hammered out due to the crystalline structure of cast metal; the most likely outcome would be the formation of a crack (...