Nothing like a little salad dressing to rescue an 800-year-old cathedral. British scientists and archaeologists tasked with saving York Minister, a stunning cathedral in northern England, say olive oil may do the trick, NPR reports. The oil's main ingredient—oleic acid—could protect the building's stones from acid rain while allowing nasty pollutants to seep out into the air. The problem: Pollution dating back to the Industrial Revolution is causing York Minister's limestone to slowly come apart.
"The salts actually build up in the microstructure of the stone and eventually crack it, and large features will start to fall off the building," says one expert. Others have also tried to protect the medieval structure, which took 250 years to build and has already withstood lightning, fires, pillaging, and looting. An earlier experiment with linseed oil actually damaged and darkened the stone, but inspired the olive-oil idea. Experts plan to give it a go after testing is completed on sample stones.