First, such items should never be labeled with Sharpies, "white-out," fingernail polish, or other such products. Even tiny amounts of these will contaminate samples severely, so that it can be difficult or impossible to perform successful FTIR analysis. Any items that might be considered for FTIR analysis should not be labeled directly, but rather can be wrapped in aluminum foil for protection (although this is not necessary), then placed in a paper bag. The paper bag should be labeled with a LEAD PENCIL, not with a marker or pen.

Second, the artifacts or samples should be stored in paper bags, not in plastic. A sample placed in a plastic bag is confined in a small space with the chemicals that "off-gas" from the plastic, although this is not as severe a problem as the labeling described above. The chemicals that "off-gas" are also confined inside the bag and have no where to go except into the items placed in the bag. Wrapping a sample in aluminum foil, then placing it inside of a plastic bag does not protect the sample. Think of being trapped in a small room with smokers. Where does the smoke go? Are you protected if you wear a medical mask or put perforated aluminum foil over your mouth and nose? What do you smell like when you exit the room? This is a real world example of what happens when a sample is placed in a plastic bag, except that it is the bag itself that is "off-gassing" chemicals into the interior space. It appears that this "off-gassing" continues for the life of the plastic bag. If your samples have been kept in plastic bags, simply transfer them to paper bags and note (in PENCIL, on the bag) that they were removed from plastic bags. Existing contamination from the plastic bags will gradually fade.