The plastic ones are disposable (as far as Chaburos are concerned). The Bnei ha’Chabura usually take them for their kids (and presumably throw them before Pesach or at least put them away). They’re fairly easy to obtain from Matzah bakeries, at least here in E”Y.
The plastic ones are absolutely assur. They are not in our mesorah. In my family, we eat only matzah that has holes punctured with a hand-carved wooden reidel. The matzah MUST have wood splinters baked in or it’s passul for use as matzas mitzvah.