HOW TO CLEAN A BRONZE SCULPTURE?
Knowing how to clean a bronze sculpture without damaging it requires some expert knowledge. Recently, we had an enquiry from the archivist at Pembroke College, Oxford – Amanda Ingram.
The college had a splendid bronze bust which had, unfortunately, been languishing in a basement for some time. It was to be relocated to a prominent position in the college but it had to be cleaned. Amanda came to us for advice.
She said, “I would like to clean our bronze sculpture. I have given it a light wipe with distilled water to remove surface dust but there is quite a lot of it which has a kind of fine crust on the surface. It is as if someone has wiped it with a dirty rag (for example containing paint residue) and this has set on the surface. The other thing is that it looks like parcel tape or something has, at some point, been stuck on his face and has, likewise, left a hard adhesive residue.”
Our first suggestion was to try a solvent like acetone to remove the parcel tape residue.
Amanda asked, “is nail varnish remover a suitable acetone or does it need to be a purer version? And, what sort of soap is best to use?”
Our advice was to buy a pure acetone as nail varnish remover often has added components. This worked extremely effectively.
Regarding the wiped, crusty areas, we recommended trying to clean them first with some soap and water and if it worked to apply a couple of coats of micro-crystalline wax to the surface for protection. We recommended trying a small patch first and look at the outcome before going too far.
Although neutral soap solution is always a safe bet when cleaning a bronze sculpture. it’s not an ideal method for removing stubborn dirt. It can require more rubbing at the bronze’s surface which isn’t a good idea. Diluted Vulpex soap is slightly alkaline, but providing it is properly removed, can be a gentler method.
Amanda returned a short while later reporting that, unfortunately, the dirt was still stubbornly in place.
Our advice was to try a little abrasion with something very fine like bronze wool. Most important was just to do a small area as a test to ensure no damage was caused. This method of cleaning could be combined with a little soap solution.
Amanda’s results speak for themselves. She applied Renaissance Micro-Crystalline wax after for the statue’s protection. Her careful approach has yielded some great results. Well done, Amanda!
If you’d like to learn more about how to care for bronze, take a look at our online course. It’s been created for custodians of bronze sculpture and features so that you can gain knowledge about bronze conservation in your own time, and become a bronze champion!