The processes that cause some galaxies to stop forming stars and how such galaxies stay quiescent remain open questions. While quiescent galaxies have comparable amounts of cool gas in their outer circumgalactic medium (CGM) compared to their star-forming counterparts (e.g. Chen+ 2018), they have significantly less interstellar gas (Magdis +2021). Theories point to dynamical interactions with the hot corona as the primary process preventing cool gas from reaching the galaxy (Afruni+2019). However, there is a lack of understanding of the inner regions of the CGM of quiescent galaxies that is due to limitations in standard quasar-sightline methods, which lack spatial information in the needle-like beam. I will present work using galaxy-galaxy scale strong lenses which probe the inner 10--20 kpc of massive quiescent galaxies. We use Keck/KCWI IFU spectroscopy to spatially resolve MgII absorption around the quiescent galaxies tracing large amounts of cool (10^4K) atomic gas. Even at these close impact parameters, we find a comparable amount of cool gas compared to star-forming galaxies. Additionally, we show through detailed lens modelling of high resolution Hubble imaging that the lens model of one system reveals a diffuse component of significant mass consistent with the spatial extent of the MgII absorption. Our work shows the power of galaxy-scale gravitational lenses to not only probe the gas in the inner regions of the CGM, but to also independently probe the mass of the CGM due to its gravitational effect.