In many astrophysical scenarios, the charge of the black hole is often neglected due to unrealistically large values of the charge required for the Reissner-Nordström spacetime metric. However, black holes may possess a small electric charge due to various selective accretion mechanisms. We investigate the process of ionization of a neutral particle in the vicinity of a weakly charged non-rotating black hole and calculate the energy of an ionized particle in a chosen scenario. High energy obtained by a charged particle after the ionization process can serve as a distinguishing signature of the weakly charged black holes.