Last week he took the Independent to see the corpse behind the door. But it was not the founder of the Soviet Union, for Dr Kozeltsev has a new client who is benefiting from the secret technology developed to keep the world's dead Communists looking youthful. She is a 2,400-year-old ice maiden from Siberia, whose preserved corpse was recently discovered by archaeologists excavating in the Altai mountains, near the Chinese border.
"The Lady," as she has been nicknamed, kept her looks over the centuries because water trickled into her tomb and froze her in a block of ice. When the archaeologists first uncovered her, her skin was as white as the day she died and covered with tattoosof deer and snow leopards. But they poured hot water over her to melt the ice and the skin darkened in the atmosphere. Dr Kozeltsev, of Moscow's Centre for Biological Structures, has been working to return the skin to its original colour and reveal the tattoos. Soon "The Lady" will be ready to go on show to the public.
The excavation, led by Natalya Polosmak, of the Siberian branch of the Russian Academy of Sciences, took place in the summer of 1993. On a dig in 1949, archaeologists found a male mummy with similar tattoos in one of the many burial mounds that litter the "Pastures of Heaven", the high steppes of the Altai region. But at a place called Ukok, a few hundred yards from the fence separating Russia from China, Ms Polosmak and her team from Novosibirsk found a tattooed woman, in far better condition than the man, who is now in the Hermitage Museum, St Petersburg.
Russian border guards had tipped off the group to dig at Ukok, which means "the end of everything," but still the archaeologists nearly missed the tomb. There was a later grave above it, which had been looted. But they persisted and dug to where "The Lady" had lain, undisturbed, since about 400BC.
The occupant of the grave above had protected her from the robbers. "It was a stroke of incredible luck," Ms Polosmak said. "It is an archaeologist's dream to find a grave untouched by looters and frozen into the bargain."
The burial chamber was built of larch logs, like the little cabins you see all over the Russian countryside to this day. When the archaeologists opened it, they could smell the mutton and horsemeat that had been put on a table to provide sustenance for "The Lady" on her last journey.
"The Lady," tall for her time at 5ft 6in, lay on her side, as if asleep, in a wooden coffin at one end of the chamber. She was dressed in white woollen stockings, a woollen skirt with horizontal white and maroon stripes, and a yellow Chinese silk blouse with maroon piping.
The blouse was an old one which had been mended several times. Ms Polosmak said: "Her tribe had plenty of wood and wool but silk was a rare, traded item and, therefore, had to be made to last."
She must have belonged to the elite of her society to have been buried, as she was, surrounded by six horses to transport her in the after-life.
She also took with her a silver mirror and decorative snow leopards carved from wood and wrapped in gold leaf. "We would not have been so happy if we had found solid gold," Ms Polosmak said. "These were everyday things. Through them we see life as it was."
"The Lady," who was in her mid-twenties when she died, apparently of natural causes, had been partially mummified but not like an Egyptian queen, in balm and bandages. Instead, the undertakers had removed some of her organs and stuffed the body with grass and wool.
The most interesting thing was that her head was shaved and she wore a wig and a tall wooden head-dress decorated with cats and swans.
This, in addition to many strange animal tattoos, persuaded the archaeologists that she was probably a shaman, or religious leader in touch with the spirit world.
The find proves that at a time when only bears and wolves roamed where Moscow now stands, southern Siberia had a sophisticated culture. "The Lady" belonged to a steppe tribe called the Pazyryks, close relatives of the Scythians, who lived around the Black Sea.
The Pazyryks, who had European rather than Mongoloid features, were nomadic horsemen and shepherds. Probably they worshipped the Sun and Moon as well as the animals featured in their strange body-art.
Perhaps they believed, as the locals do to this day, that on the high steppes they were closer to Heaven than ordinary mortals. It is still regarded as a sacrilege to shout here, in case you disturb the spirits of the air.
The removal of "The Lady" from the remote Ukok plateau should have been an occasion almost as solemn as her burial. Six of Ms Polosmak's students carried her lovingly on a bier through the fields of wild flowers to a helicopter. But the helicopter had anengine failure and made an emergency landing on its way to Novosibirsk. "The Lady" had a bumpy ride not recommended for a woman of her age. The archaeologists tried not to dwell on the idea that those who disturbed the grave might be cursed.
What with the accident and the hot-water treatment, "The Lady" was not in good condition when she was handed to Dr Kozeltsev in Moscow. "Ideally," he said, "the archaeologists should have refrigerated her as soon as they found her and called me immediately."
After working on the body for several months, Dr Kozeltsev and his four assistants have succeeded in restoring the whiteness of the Pazyryk woman's skin and making the tattoos visible again.
In the laboratory "The Lady" is lying under a plastic sheet on a table above a bath of chemicals. She has been soaked in the bath for many weeks and is now drying off. For the time being, she is headless: her skull has been sent across town to the Gerasimov Ethnographic Institute, which produces sculpture-like reconstructions of the heads of dead people.
The skeleton shows through the skin in many places. But the clasped hands are touchingly preserved and the skin all down the left arm is intact. This is where you can see the swirls of dark-blue tattoos, starting with a kicking deer on the shoulder. A Siberian specialist is due in Moscow soon to try to interpret the meaning of the tattoos.
As soon as Dr Kozeltsev gets the skull back, he can finish his job. On a wad of cotton wool, he has saved the neck vertebrae so he can join the head to the body. Then she will be placed in a showcase of non-breakable glass and will be ready to return to the archaeologists who found her.
When "The Lady" makes her public debut in April, it will not be in Siberia or even Moscow, because there is no money from either the state or private sponsors to pay for her exhibition at home.
Instead, she will go on show, with the bust, her clothes and a collection of Pazyryk artefacts, in South Korea. After that, unless Russia's economic situation improves, she faces a future living out of a suitcase on a permanent world tour.