Soap is an unexpected threat to priceless works of art

Priceless works of art have an unexpected and deadly foe, and we don’t mean cat burglars or forgers. We’re talking soap!

Tiny formations of lead-based soaps are threatening paintings across the world, reports Artnet.

Scientists have identified the presence of the soap — which forms when fatty oils naturally present in oil paints mix with with lead ions from the pigment — in works by Francisco Goya and Vincent van Gogh to Piet Mondrian, as well as works by contemporary artists. According to Artnet, the issue is so prevalent that forgers even incorporate lead soaps to make a painting appear older.

Conservators have been working to solve this problem for almost 20 years, but experts have yet to figure out how to stop it. The soapy deposits give paintings a hazy appearance, can cause paint to flake off the canvas in layers, or the soaps break through the paint and create tiny craters.

“It’s really bizarre,” Ellen Baxter, the chief conservator of Pittsburgh’s Carnegie Museum of Art, told Artnet. “For things that are supposed to be so inanimate, paintings can be really animated… it’s always an adventure.”