Observation-Based Slicing (ORBS) is a recently introduced program slicing technique based on direct observation of program semantics. Previous ORBS implementations slice a program by iteratively deleting adjacent lines of code. This paper introduces two new deletion operators based on lexical similarity. Furthermore, it presents a generalization of ORBS that can exploit multiple deletion operators: Multi-operator Observation-Based Slicing (MOBS). An empirical evaluation of MOBS using three real world Java projects finds that the use of lexical information, improves the efficiency of ORBS: MOBS can delete up to 87% of lines while taking only about 33% of the execution time with respect to the original ORBS.