During the long lifespan of a metal sculpture, restoration interventions are occasionally necessary. Damage can occur as the result of accidents during transport, because of structural problems, or due to the influence of weather and environment. In the case of sculptures situated outside, efflorescence or cracks due to frost can be caused by residues of the inner core and corroding reinforcements. The problem of metal conservation is also presented by structures in public spaces. Depending on the particular region, substantial corrosion damage also sometimes results from high concentrations of sulfur in the air.

Restoration work consists predominantly of retouching the patina, fixing cracks and breaks, creating drainage openings, and careful cleaning and conserving with wax.

Every piece has its own multi-layered and interdisciplinary requirements, and demands careful and complex solutions and decisions. The prime concern in all restoration work is dealing with the original gently and with extreme care, and retaining its historicity. The reversibility of all interventions is, therefore, when possible, of the greatest importance. The Kunstgiesserei cooperates closely with monument conservators and employs a specially trained restorer. Traces of history and imperfections should be handled with reserve. In restoration, damage resulting from past interventions often presents a greater problem than the original damage itself.