HOUSTON, Texas For the Apollo astronauts, it was like bringing home the goods. Covered from helmet to toe with lunar dust, the "dirty dozen" Moonwalkers from 1969 through 1972 snagged, bagged and tagged 840 pounds (382 kilograms) of rock and other surface material.

Today, much like King Tutankhamens holdings, the "Apollo collection" is vaulted treasure.

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Safely sequestered here at the NASA Johnson Space Center (JSC), Moon specimens are protected from natural hazards such as tornadoes and hurricanes. Sealed for study in nitrogen-filled cabinets, the lunar sample inventory is also guarded against Earth contamination, preserving the history-telling tales they hold about the origins of our solar system.

But new studies of Apollo lunar materials are showing just how contaminated pristine samples can become. Those investigations are expected to help clean up NASAs act in handling an assortment of Mars's rocks, or pieces of comet or asteroid returned to Earth in the future.

"It was quite alarming," said Andrew Steele, an astrobiologist at NASAs JSC from the University of Portsmouth in the United Kingdom, who thought he was looking at hairs from an astronaut. But they turned out to be brush fibers, he said.

Working with lunar sample curators, Steele is part of a team using powerful instruments to eye the condition of select Moon materials. He not only found brush bristles, but bits of plastic, nylon and Teflon, as well as a few earthly organisms having a picnic within lunar samples.

"Some of them are pretty snotty," Steele told SPACE.com.

Steele looked at a cross-section of lunar samples known to be contaminated, as well as a pristine core of lunar regolith brought back by Apollo 15 astronauts. Brushings from astronaut suits, along with bits of lunar leftovers swept from cabinets and control panels were studied.

All of the specimens inspected by Steele, including a core sample, show evidence of contamination, mostly by plastics, he reported during the 32nd Lunar and Planetary Science Conference, held March 12-16 at the NASA center.

Former Apollo 17 astronaut, Harrison "Jack" Schmitt, said his impression is that lunar samples have been taken care of well throughout the years.

"I am sure that there may have been exceptions, but reputable researchers cannot afford to work on contaminated samples," Schmitt said in a later interview. At the time, there were unavoidable incidents of contamination, he said, which everyone knows occurred during collection, transport, and handling prior to distribution.

Schmitt said that the lunar sample containers were unable to retain a vacuum and most samples came back in bags without sample box protection. Spacecraft atmosphere and Earth's atmosphere contaminated the samples at that point, he said.

"Isotopic analysis and other techniques, however, can eliminate most if not all of these contamination signals. Good research must always examine the possibility of contamination and, if possible, subtract its effects," Schmitt told SPACE.com.

Future sample-return missions from Jupiters enigmatic moon, Europa, as well as Venus and Mercury are possible too, Cyr said. In Apollo, and in readying for future sample-return projects, "the primary lesson is that curation starts at the beginning, during planning and mission design phases," she said.

Steele said that his work is meant to help plot out Mars sample-return missions. The techniques and tools being utilized, he said, can be applied to spotting evidence for Martian life versus contamination within samples.

"Theres a lot of new technology available, some of it from the silicon conductor industry," Steele said. "The flip side of our work in spotting contamination and terrestrial life in samples is also, ultimately, to find life in extraterrestrial materials," he said.