Recently, passive Radio Frequency Identification (RFID) systems have received an increased amount of attention as researchers have worked to implement a stable and reliable system. Unfortutely, despite vast improvements in the quality of RFID technology, a significant amount of erroneous data is still captured in the system. Currently, the problems associated with RFID have been addressed by cleaning algorithms to enhance the data quality. In this paper, we present X-CleLo, a means to intelligently clean and transform the dirty data into highlevel events using Clausal Defeasible Logic. The extensive experimental study we have conducted has shown that the X-CleLo method has several advantages over currently utilised cleaning techniques and achieves a higher cleaning and event discovery rate.