The silver processional statue of St. Philip of Agirra at the Haz-Zebbug Parish Church in Malta is considered one of the most important silver statues of the 19th century. Made by renowned sculptor Luigi Fontana in Rome, the statue was commissioned in 1860 and completed in 1863 under the direction of Johann Friedrich Overbeck and Tommaso Minardi. The statue is 290cm tall and consists of 69 silver sheets and 6 casts, made with Silver 800 metal. The wooden anima was carved to hold the embossed silver plates, which were joined and polished to look like a whole. The statue was displayed at the Vatican in July 1863 and was blessed by Pope Pius IX before arriving in Malta on July 29th. The statue was transferred to the parish church on May 8th, 1864.

The conservation of the statue required a team of specialists in various fields of conservation who contributed to the treatment process. Before the work began, a detailed analysis of the problems the statue was facing was documented through photography, graphical mapping, and reporting. The problems were divided into those caused by natural deterioration factors, damage due to handling, and others caused by past interventions or indirect effects of these interventions.

The tarnishing and corrosion of the statue was caused by various pollutants such as sulphides, chlorides, and nitrates from sources such as car exhaust, burning candles, incense, and fireworks. The horizontal flat surfaces of the statue, particularly the base, showed heavier tarnishing and exhibited a dark grey color. A brown corrosion product was found around the plate edges, particularly on the pleated alb, which was possibly due to the use of cleaning products that had not been completely removed. Light green corrosion was found in flat areas of the statue, particularly around the wrist and cuff of the right hand, which was a possible reaction with commercial cleaning product residue. Tarnishing may have also been caused by the release of volatile gases from the wooden niche that housed the statue.

The polished areas of the chasuble were heavily stained with differential coloration, which was determined to be the result of a past repair intervention where damaged areas were filled or joined with a low silver alloy. This intervention resulted in the application of silver solder alloy with an uncontrolled flux that migrated along the flat areas, altering the appearance of the silver surface.

The mechanical damage to the statue was caused by its processional nature and its composite construction of wood and metal parts. Abrupt movement during processions and lifting onto the shoulders of statue bearers put stress on the structure, causing the slightest looseness to become more pronounced. The fact that the plates were held in place by hammered nails into the wooden support resulted in movement and further damage, especially when the nails put pressure on surrounding plates or cast parts. The detached wooden pieces inside the statue put severe pressure on various parts of the statue, opening wider gaps with every abrupt movement. This damage was evident in areas subject to shear tension, such as around screw and nail holes and in tears in the plates and cast pieces, such as a torn hole on the edge of the raised hand and the tip of the beard.

Before the actual conservation intervention, a team of experts from different fields was formed to plan and execute the project. The team consisted of experts in metal and wood conservation, scientific research, and art history, who were all concerned with following international conservation ethics and preserving the original integrity of the sculpture. Photographic documentation was taken before the intervention and was continued throughout the process, capturing every step of the dismantling and conservation of the statue. Site meetings were held regularly to examine the statue and assess progress.

Cleaning tests were performed on different silver areas to determine the best solution for conserving the statue. The best options were chosen from these tests and used during the cleaning process. The original plan was to not dismantle the statue, but due to the extent of damage and past interventions, some parts had to be taken apart. Dismantling the statue proved challenging due to the use of iron nails and overlapping metal plates, but the wooden anima beneath the silver plates needed to be consolidated for preservation. The wooden anima was cleaned and repaired in a manner which respected the integrity of the material as well as reversibility.

The cleaning process varied depending on the extent of damage and corrosion. Tarnished areas were first degreased with a mild solvent and then cleaned with a light detergent solution and steamed. The surface was then hand-polished to bring back its original shine while maintaining its patina acquired over time. Areas with soldering stains were cleaned using a fine grade emery cloth, carefully removing the solder without affecting the original texture. The final result was a polished surface that was as close as possible to the original intended appearance of the statue.