Saliva cleaning isn’t a cure-all, but it is one of many tools conservators may reach for when in need of a gentle, yet surprisingly powerful, cleaning agent. But saliva cleaning is a job best left to professionals. In other words, don’t try this at home.
Why We Sometimes Use Spit to Clean Paintings
Yes, it’s really a thing—and it’s surprisingly effective
Paintings conservator Devi Ormond cleans Jacob Blessing the Sons of Joseph. Painting courtesy of the National Gallery of Ireland collection
Body Content
When paintings at Getty need cleaning, conservators have an arsenal of tools they can choose from, including a variety of solvent and water-based cleaning systems.
But sometimes, one of the simplest methods is the most effective: saliva cleaning.
Yes, you read that right. Historically, human saliva, which can be considered a mild enzymatic solution, is a commonly used cleaning agent at art museums. “It’s actually one of the first treatment procedures I learned in training for conservation,” said Kari Rayner, associate conservator of paintings at the Getty Museum. There are a few reasons why saliva cleaning can be a surprisingly helpful conservation technique.
The Power of Saliva
Human saliva is well-suited for removing dust, dirt, built-up grime, or foreign materials like nicotine from artwork. It contains enzymes including amylase and lipase, which break down starches and fats sometimes found in grime—not surprising considering saliva’s role in helping you break down food! The pH of saliva can vary from person to person, but on average is slightly acidic, which can improve cleaning performance. Its warm temperature can also encourage removal of grime and other non-original materials.
Developments in cleaning chemistry have allowed conservators to identify the many different factors that influence the efficacy of cleaning, finely tailor solutions for safely removing surface grime, and even imitate natural saliva in formulations described as “synthetic saliva.”
In a practical sense, human saliva is no-cost, sustainable, and non-toxic. The technique is often particularly suitable for paintings that are already protected with a layer of varnish, which provides a barrier between the saliva and the paint itself. Even if varnish removal is the eventual goal of a treatment, removing surface grime is often an important initial step in getting to know the painting and its condition.
Jacob Blessing the Sons of Joseph, c. 1620, Guercino. Oil on canvas, 170 x 211.5 cm. Image courtesy of the National Gallery of Ireland, licensed under a Creative Commons Attribution 4.0 International License
Devi Ormond, Getty’s associate conservator of paintings, cleaned this painting while it was on loan from the National Gallery of Ireland in 2016.
When approaching surface grime removal, a conservator typically carries out several small tests in inconspicuous areas to first determine whether there are any original materials present that might be sensitive to water-based materials. Gaining an understanding of the painting’s construction and artist’s technique is crucial. During this process, “if you do a test side-by-side with water and saliva, oftentimes saliva performs better in terms of grime removal,” Rayner said. “This method is only chosen after careful testing.”
Jacob Blessing the Sons of Joseph was cleaned using saliva—these swabs demonstrate how much grime can accumulate on the surface of a painting.
