ST. PETERSBURG — From our breath to dirt particles on our clothes, everything about us contributes to art's slow deterioration. The dilemma for museums: how to protect precious artwork while making it accessible to vast numbers of people.

Conservationist Rustin Levenson is one of the human stopgaps who makes both possible. She usually works in a private lab, but for the next two weeks, patrons have the rare opportunity to see her clean and repair inch by inch four of the largest and most popular paintings at the Dalí Museum.

The four masterworks by Spanish surrealist Salvador Dalí are also those deemed most in need of help: The Discovery of America by Christopher Columbus (1958-59); The Ecumenical Council (1960); Galacidalacidesoxiribunucleicacid — Homage to Crick and Watson (1963) and The Hallucinogenic Toreador (1969-70). The monumentally sized works, which measure at least 10 feet in height and length, have been moved from their regular home in the permanent gallery and propped against walls in the Hough Family Gallery.

During the conservation project, titled "Stripped Bare and Bathed: the Preservation of Dalí Masterworks," visitors can watch during museum hours, and Levenson and her colleagues will answer questions daily at 3 p.m. Their work will be projected live onto a gallery wall.

"There is a mystery to conservation," says Hank Hine, director of the museum, "the chemicals, the arcane technology. But most of it is very hands-on and we wanted to demystify and dramatize the technique."

On Monday, the first day of the project, Levenson and eight other conservators started with two of the paintings, Discovery of America and Ecumenical Council. Levenson said Council will take the most time. Looking at the sides where the canvas is nailed to its wood frame, she said, "It looks like someone used a machine gun."

It has been restretched several times before it came into the Dalí's collection, meaning the canvas was removed from its wood frame and reattached. The fabric is riddled with uneven holes from old nails.

Also in the course of restretching, the canvas was not put on straight, so thin lines of unpainted canvas are visible on two sides. For an unknown reason, Dalí used "flimsier fabric" for the painting, and that also is contributing to the canvas' fraying. And now, well past 40, the painting is in great need of cleaning.

Levenson and her team begin by testing a gentle, water-based solution on a tiny bit of every color on the canvas to make sure it removes only dirt, never paint. The cotton tips are taped to a sheet of paper to compare shades of grime. Then the painting is divided into sections with hanging strings and each person goes inch by inch, slowly swabbing a section.

The painting also has a small hole in the canvas, incurred during its journey to or from Australia for a special exhibition. It might need retouching with paint. If paint is applied to any work it must be used according to the universal conservation dictum: Do nothing that can't be undone. In the case of these paintings, which have a protective varnish, the paint will go on over that and can be easily taken off in the future.

The project costs $100,000, funded by a $50,000 grant from the National Endowment for the Arts, private donations and the museum.

It's a laborious process. Levenson spent several weeks evaluating the paintings and writing damage reports. It took her two weeks to figure out and mix the right chemical solutions for each painting.

"It's more complicated than it looks," Levenson says. "It's part art history, part science. No one should ever try to clean art at home. The worst damage I have seen was by untrained restorers."

Levenson has worked at Harvard University's Fogg Museum, the National Gallery of Canada and the Metropolitan Museum of Art. Now she has her own company with studios in New York and Miami and a client list filled with museums and private collectors. The Museum of Fine Arts, St. Petersburg, for example, hired her in 2004 to conserve one of its paintings by Claude Monet.

She says the best way to see the "before and after" effect is to come during the cleaning when the brightness of the dirt-free canvases will be more obvious.

As paintings go, the ones by Dalí are in pretty good shape, needing mostly just cleaning. Levenson refers to a painting by Gustave Courbet waiting in her studio. Insects, she said, have eaten away almost all of the canvas leaving nothing but paint and a coating underneath.

"It looks pretty scary," she says, "but I think we can fix it."

Lennie Bennett can be reached at (727) 893-8293 or lbennett@tampabay.com.