a process is provided for producing a plastic part that cannot be colonized by germs and / or fungi . the process includes the step of sequentially treating the plastic part with a swelling agent to provide a swollen plastic part , and then treating the swollen plastic part with a solution of a water - insoluble compound containing a bactericidal and / or fungicidal metal , where the solution has a bactericidally and / or fungicidally effective concentration of the insoluble compound .