From the Conservator's Bench: Care and Maintenance of Bronze Sculptures
John McNulty's interest in art began when he took advantage of a free Charter Membership offered by the Gilcrease Museum. Since then, he has begun to collect artworks that have captured his interest. He asked Gilcrease Museum Chief Conservator Victoria Book about care and maintenance of his two bronze sculptures.
"I read online that you should oil bronze sculptures occasionally to protect them. Is that good advice?" McNulty asks.
Indoor bronze sculptures typically require very little direct care, Book says. Nearly all bronzes will have had a surface finish, often including wax, applied to the sculpture during its production. The finish will remain stable as long as the sculpture is kept indoors and dry. Never apply any oil to sculpture. Oil might make it look bright for a little while, but it will darken and become sticky overtime, attracting and embedding dust.
To care for a bronze sculpture in good condition, all you need to do is dust it occasionally (no more than once a month) with a very soft cloth or artist's brush. If dust remains stuck to the surface, you can dampen a cotton swab with slightly soapy water (one drop of dishwashing liquid detergent into 2-3 cups of water) and gently swab the dusty area, then rinse the area by swabbing again with clean water. If it looks as though you have removed wax in addition to dust, you can apply a very thin layer of an oil-free paste wax (such as Renaissance®, Butchers® Paste, or Trewax® Paste wax) with a cotton swab, and then buff it gently with a clean soft cotton pad or towel.
Most bronze sculptures have a chemical patina to tint the surface of the bronze that can be subtle shades of brown or bluish-gray. Be careful not to remove any of the patina or applied color when cleaning.
If you notice light green powder "erupting" in crevices, this could be a sign of incipient corrosion called "bronze disease" that can become very damaging, and the sculpture should be taken to an objects conservator for assessment and treatment.
If you have questions about artistic techniques or preservation, you can ask Victoria Book Lupia, our chief conservator. Send questions to: GMConservation@utulsa.edu.