A study of the influence of the concentration of secondary fluor, high concentrations of primary dopant, diffusion enhancer, and stabilizer, on radiation hardness is presented. It is concluded that the diffusion enhancing technique is the most powerful method for improving rad hardne5s. A new polystyrene scintillator which contains 2% pT & 0.02% POPOP and 20% diffusion enhancer and 0.02% stabilizer gave 91 % of initial light output immediately after 3MRad in air. Data are presented that show that scintillator prepared from commercial polymer is more radiation hard and has greater light output than scintillator prepared from monomer. It is assumed that this difference is due to different molecular weight distributions. Some protocols for acceleration of aging (yellowing and crazing) are presented. It is shown that one of the main reasons for aging of plastic scintillators is residual monomer.