Intrigued with the potential of such a process, MTEC researchers focused their early R&D on removing the chemicals from the rubber to purify it. However, this proved to be an exceedingly difficult task because even though the sludge was primarily rubber with a small percentage of residual chemicals, there was no easy way to viably remove the chemicals to make usable rubber. In addition, such an approach proved that it was nearly impossible to yield any significant volume of marketable fertilizer.