Commonly used liquids have a powerful effect on the tribocharge patterns formed by rubbing polyethylene (PE) and poly(tetrafluoroethylene) surfaces. Solvents previously absorbed on PE specifically suppress positive tribocharge deposition. When applied to previously tribocharged surfaces, they also behave as charge-suppressing agents or transfer media. All these unprecedented results verify a new mechanochemical model that was recently introduced to explain the hitherto challenging problem of triboelectricity formation.