The tables in the basement of the Municipal Archives are covered with household staples: cotton swabs, tweezers, food strainers, measuring cups, ashtrays and other materials.

None are items that one would expect to find in a professional art conservation laboratory. But they are tools used by a group of government workers who wash and care for some of the oldest existing maps and architectural drawings of New York City. They call themselves “dry cleaners.”

“It’s like being a tailor, but a tailor for paper,” said Pauline Toole, commissioner of the city’s Department of Records and Information Services, which oversees the archives at 31 Chambers Street — what was once the Hall of Records, but is now the Surrogate’s Courthouse.

The building is home to 243,000 cubic feet of records — enough to cover more than four football fields — including maps, photographs, film spools and birth, death and marriage certificates that tell the story of the city’s past. The last four years have seen a push from researchers and archivists to digitize the annals, slowly making them more accessible to the public, but many of the faded, fraying documents are almost too fragile to endure that process, according to the conservators there. Among the endangered records are hundreds of maps of post-colonial New York, created as early as the 1700s, rolled tightly into cardboard wrapping and stored in the city’s proverbial attic.