Disclosed is a process for treating at least one hollow body made of thermoplastic material, such as a preform or a cap, the treatment process successively including at least the following steps: a first step, consisting in treating at least the inside of the hollow body using hydrogen peroxide； a second step, consisting in heating the hollow body； a third step, consisting in treating the hollow body with plasma in order to reduce the concentration of hydrogen peroxide residues. Also disclosed is a plant for manufacturing containers in which the process is carried out in particular by way of a unit for the plasma treatment of the preforms.
