Post-processing of tool coatings is an essential way to remove defects, enhance coating properties, and improve tool performance, where abrasive jet machining plays an important role. This paper introduces a novel application of self-developed elastic abrasives to the post-treatment of coated tools, with a comparison against hard abrasive (Al2O3) jet machining (HAJM). The results demonstrate that EAJM significantly reduces the surface roughness of the coating and enhances the wear resistance of milling tools across a wide range of jetting parameters without damaging the coating. Conversely, HAJM yields more pronounced improvements in physical properties such as coating hardness, elastic modulus, and residual stress, and also significantly enhances tool performance, albeit with a need for precise process parameters. Overly aggressive HAJM parameters can lead to diminished coating performance and reduced tool life. Additionally, the study reveals that the improvement in tool life is closely linked to the physical properties of the coating, which contributes to the enhanced performance observed with HAJM-treated tools. To further investigate this, a mathematical model was established to analyze the coupling effect of jet pressure and time on tool life. The proposed model identifies the optimal ranges of the jetting coefficient for HAJM and EAJM as 326–4870 kPa·s and 1061–17,780 kPa·s, respectively, offering a novel approach to optimizing tool performance and life.