The possibility of producing, by quenching, new transparent heavy polystyrene scintillators with a light output of similar to 32% of that of anthracene and with a total concentration of organometallic additives of similar to 17 wt % is shown. Doping of plastic scintillators with a set of different organometallic additives improves their ability to absorb soft gamma-quanta and makes this absorption more uniform for different energies.