CLEVELAND — The Army believes in spit and polish. So does the Cleveland Museum of Art.
Bizarre as it might seem, conservators at the museum clean at least several works of art every year by using cotton swabs dampened in their own mouths.
On official reports, this is described euphemistically as cleaning "with a mild enzymatic solution."
But in the museum's third-floor conservation studios, where paintings are propped on easels like customers awaiting treatment in a beauty salon, the language is a little more direct. Up there, it's called spit cleaning. And after centuries of common use, it is still a widely accepted way to remove dirt from paintings, sculptures and decorative objects.
"It's not a new technique at all," said Marcia Steele, the museum's conservator of paintings. In fact, she said, the literature of art conservation contains descriptions as far back as the 18th century of conservators using saliva to clean paintings.
Of course, back then, art conservators often did as much harm as good. They cleaned paintings with urine, which contains ammonia, and with wine, which contains alcohol. They rubbed paintings with pieces of damp bread or raw potato halves.
But while those methods have been dropped, scientific analysis supports the use of saliva as a good, safe way to remove certain kinds of grime, particularly on varnished surfaces. In essence, the proteins in saliva that break down food also break down dirt and grime.
The universal availability of the material also explains why companies that supply museums with conservation products have not developed a synthetic version of saliva. The conservation field is so small that it probably would not make economic sense to go to the trouble, said Bruce Christman, the museum's chief conservator.
Most commonly, spit cleaning is the simple first step in a longer and far more complex process that can include the removal of discolored varnish or the removal of posthumous touch-ups that might obscure the original intentions of an artist.
The real surprise, given the ubiquity of spit cleaning, is that it attracts so little attention, especially at a time when museums are mounting exhibitions and organizing lectures on conservation methods.
"It may be overlooked because it is such a basic technique," said Albert Albano, director of the Intermuseum Conservation Association in Oberlin, a nonprofit service that conserves artworks for dozens of museums across the Midwest. "We're talking absolutely Conservation 101 here."
Then, too, it's not the kind of thing most museums would publicize in a news release.
"We view it as just another cleaning alternative," Christman said, "although some people might think it's gross and disgusting."
Nevertheless, it is effective. For proof, consider "Oedipus at Colonos," a large French neoclassical painting by Fulchran-Jean Harriet, which recently went on view in Gallery 229 of the museum.
Dated 1798, the painting depicts the self-blinded Greek king, made famous by Sophocles and Freud, comforting his daughter, Antigone. They are seated on a bench in front of a stone pier, with a stormy landscape in the distance and dark birds hovering portentously overhead. Raking light infuses the scene with drama, color and mystery. It also contributes to the rich shading of the gowns draped over Oedipus and Antigone.
But before the museum purchased the picture, its beauty was muffled by orange-brown grime, reportedly caused by cigarette smoke in the home of the French collector who previously owned the work.
"This was a very dirty painting," Steele said.
With permission from the collector, the museum began cleaning the work several weeks before the purchase was approved officially by museum trustees.
Working with Linnaea Saunders, a Kress Fellow in art conservation, Steele completed a scientific analysis showing that the dirt and grime rested on varnish that protected the paint layers beneath. Together, they decided that spit cleaning would be the best way to proceed.
So Saunders, 31, who has honed her skills at the museum for two years, got to work. She custom-made her own swabs, so she could make them bigger or smaller than the standard commercial size.
She also checked the color of the material coming off on the swabs to make sure she wasn't rubbing hard enough to remove varnish or paint.
And she made sure her mouth did not get too dry.
"You drink a lot of water," she said.
The painting brightened visibly as she worked. Antigone's flowing gown went from orange to pearly white. The cloudy sky became more radiant. Highlights glowed, and shadows grew more resonant.
"When you see details you've never seen before, that's really exciting," Saunders said.
It was not her first experience of spit cleaning. In a previous internship, at the Courtauld Institute of Art at the University of London, Saunders participated in the cleaning of a Botticelli painting of the Trinity.
"I got to clean the body of Christ," she said.
Despite the popularity of spit cleaning, conservators say it's not the kind of thing to try at home.
"If you have water-soluble paint layers, it would be a disaster," Christman said. He recommends that people who might want to have an artwork cleaned should see an expert conservator before doing anything.
Meanwhile, anyone who doubts the cleansing power of saliva can inspect the conservators' handiwork at the museum. It demonstrates what drill sergeants and mothers have always known: You don't always need soap and water to get out the grime.