Metal products, wooden artifacts, lacquerware, volcanic tuff, and other diverse materials were given preservation treatment appropriate to each with utmost care at the hands of specialists.
Before preservation treatment, the condition of each artifact was examined in detail with X-rays or other means. Cleaning and treatment methods were then selected as appropriate to that condition. Subsequently, dirt was carefully removed with brushes or bamboo skewers, and rust prevention, stabilization, and reinforcement treatments were conducted.
For example, in the case of an iron scabbard fitting for attaching the sword to the wearer’s belt, decorated with silver plating on the inner surface and gold inlay on the outside, the inlay parts were carefully polished after taking X-ray images and using a micro X-ray CT to verify that the metal parts were not damaged. Stabilizing treatment was then applied to prevent further rusting, and cracks were reinforced by injecting resin. Through these measures the item was restored to the beautiful luster of the time it was buried. For wooden artifacts and lacquerware, after first brushing away dirt the items were soaked in distilled water to prevent drying and stored in a refrigerator. They were then treated for preservation with high-grade alcohol or other such treatment. Blocks of volcanic tuff used as the material for the stone chamber were reinforced with organic silicate ester.