Reader Checked|RAC|Revised Reader Checked - AK - 30/01/2012
While kept at the Rockefeller Museum in East Jerusalem, many Dead Sea Scroll fragments were exposed to
|castor oil by the original team of editors in the course of cleaning the parchments. Castor oil must be regarded as a serious contaminant
|in relation to radiocarbon dating. If modern castor oil is present and is not removed prior to dating, the 14C dates will
|be skewed artificially towards modern values. In Rasmussen et al. (2001), it was shown that the standard AAA pretreatment
|procedure used in the 2 previous studies dating Dead Sea Scroll samples (Bonani et al. 1992; Jull et al. 1995) is not capable
|of removing castor oil from parchment samples. In the present work, we show that it is unlikely that castor oil reacts with the
|amino acids of the parchment proteins, a finding which leaves open the possibility of devising a cleaning method that can
|effectively remove castor oil. We then present 3 different pretreatment protocols designed to effectively remove castor oil
|from parchment samples. These involve 3 different cleaning techniques: extraction with supercritical CO2, ultrasound cleaning,
|and Soxhlet extraction—each with their own advantages and disadvantages. Our data show that the protocol involving
|Soxhlet extraction is the best suited for the purpose of decontaminating the Dead Sea Scrolls, and we recommend that this protocol
|be used in further attempts to 14C date the Dead Sea Scrolls. If such an attempt is decided on by the proper authorities,
|we propose a list of Scroll texts, which we suggest be redated in order to validate the 14C dates done earlier by Bonani et al.
|(1992) and Jull et al. (1995).