Reply To: Yellowing of archival plastic bags and tags


I have been in touch with conservators  at the University of Texas at Austin and the University of Arizona. Nancy Odegaard, Conservator, Arizona State Museum suggested that what is happening is that the plasticizer in the polyethylene bag is degrading probably in the presence of acid in the artifacts.   So, the question is, do we just replace bags at certain intervals, do we test the soil from which the artifacts came to provide a warning about which materials may degrade faster, or some combination of this and other methods.  I am mostly concerned about organic materials that we package in plastic or tin foil (carbon samples).  If we package them in acid/lignen free buffered paper are we added something to the organics that will throw off future analyses?  Should we go to Nalgene vials or bottles and what is that cost?  I am reluctant to go to glass vials and bottles because these are archaeological collections and archaeologists, myself included are not always gentle when moving boxes or bags of artifacts.

Love to hear from you all out in cyberspace.