If Christian Scheidemann had become a conservator in, say, Michelangelo’s day, his job would have been a whole lot simpler. Fading fresco? Slap up scaffolding, grab some paint and get to it.

But most artists don’t make frescoes anymore. They make works like “Blossom” — Nigerian-British painter Chris Ofili’s sensuous 1997 portrait of a bare-breasted black woman, composed, in part, of elephant dung on canvas. That’s why Scheidemann, proprietor of Contemporary Conservation Ltd. in midtown Manhattan, found himself in Copenhagen a few years ago, bent over “Blossom” with a piece of crap in his hand, Bloomberg Pursuits will report in its Spring issue.

Scheidemann had been summoned to Denmark by the owner of the piece, a modern-furniture magnate. (Ofili himself had recommended the conservator; typically, an artist’s gallery makes the referral.) A lump of feces had fallen from Ofili’s painting — compromising its integrity and potentially depressing its value — and the collector didn’t know what to do. But Scheidemann, who had previously restored Matthew Barney pound cakes that had inadvertently become infested by rats, did.

He promptly ordered a new dollop of dung, trimmed it to the proper size and plugged the gap. And where did he acquire the excrement?

“The London Zoo,” Scheidemann says matter-of-factly. “Ofili always used dung from a particular group of elephants there, like he was collaborating with them.”

Cosmetic Surgery

Scheidemann and other like-minded specialists basically do the same work as traditional conservators: performing what amounts to cosmetic surgery in order to extend the lifespan of a piece. The big difference is the unorthodoxy of the materials they’re preserving. To conserve Barney’s pound cakes, for example, Scheidemann baked new ones and then replaced the fats with resin through a process called plastination.

Not every piece of contemporary art requires such profound rehabilitation, although even the most basic maintenance is seldom straightforward. Take Dan Flavin’s minimalist fluorescent-light sculptures.

“No one who buys a Flavin ever thinks about the lights going out,” says Steve Morse, conservator at the Dan Flavin Studio in lower Manhattan. “And then, inevitably, it happens.”

When it does, collectors are often tempted to replace the bulbs themselves.

“If a collector wants to go down to Just Bulbs, they can,” Morse says. “But they’ve been known to put the wrong ones in.”

Bulbs Stockpile

The wiser course is to consult with Morse, who has “a huge stockpile of the proper bulbs,” including Flavin’s signature colored fluorescents, which are no longer in production.

“We custom order them from a manufacturer in Connecticut who uses a proprietary phosphor — the colored coating on the inside of the bulb,” Morse explains. “There’s really nowhere else to get them.”

Collectors pay for the privilege — $65 per bulb in some cases, compared with a 1970s sticker price of $2 or $3 — but no one ever balks.

“We’re talking about a group of people with a strong interest in maintaining the integrity of the art they own,” Morse says.

Sometimes it’s the simplest, most monumental works — such as Robert Smithson’s “Spiral Jetty” (1970), a 1,500-foot (460-meter) coil of black basalt jutting into Utah’s Great Salt Lake — that demand the most devotion, usually in the form of stewards who spend their days on duty, making sure the artist’s vision isn’t tampered with.

Iconic Earthwork

“What’s different is the scale,” says Yasmil Raymond, curator of the Dia Art Foundation, the nonprofit that maintains Smithson’s iconic earthwork. “It’s not just a guard — someone who stands there and ensures that no one touches the art or takes it. Today’s caretakers more closely resemble ranchers, gardeners and electricians. It’s a way of life.”

Bill Dilworth is perhaps the most monkish of these contemporary-art custodians. Each morning he arrives at 141 Wooster St. in New York, site of Walter De Maria’s “Earth Room” (1977), and passes the time tending to just that: a 3,600-square-foot (334-square-meter) space filled with 250 cubic yards (190 cubic meters) of dirt piled precisely 22 inches (56 centimeters) high.

Right Texture

Once a week, Dilworth, who trained as a painter at Detroit’s Wayne State University, blasts the Dia-maintained installation with a 100-foot hose. After washing down the walls, he begins to rake. Sometimes Dilworth rakes lengthwise, sometimes widthwise — whatever it takes to get the right texture, which is not “smooth and hard” but rather a little fluffy, “like a rug.” He’s been at it for 24 years.

Scheidemann, whose iPhone rings regularly with panicked calls from collectors, soothes their jangled nerves and, most of the time, saves their investment. But he’s also reluctant to boast.

“Our work is very discreet,” Scheidemann says. “People want us to remain very much in the background: collectors, insurance companies, galleries — whoever might want to resell a piece that could lose value if people knew we had to intervene.”

Fine-Art Fixers

The solution to your next contemporary art catastrophe starts here.

Lydia Beerkens Beerkens works with museums and private collectors from her studio in the Netherlands. Her specialties include large-scale outdoor installations and sculptures in fiberglass, metal and wood.

Christian Scheidemann Manhattan-based Scheidemann is a true generalist; he’s worked on pieces by Matthew Barney, Robert Gober and Takashi Murakami, among many others.

Philip Young A former molecular biologist, Young trained at the Tate Gallery in London and the National Gallery in Washington before starting a private practice in 1987. Young’s major clients include Damien Hirst and the White Cube and Gagosian galleries, and his new London studio is designed to accommodate exceptionally large pieces. (phil@pyc.uk.com)