Rule reminder
Quick reference: ESSERE + pp = state/condition; VENIRE + pp = active process, habitual action (no compound tenses); ANDARE + pp = obligation/necessity. All three participles agree with the subject in gender and number. In compound tenses (passato prossimo, trapassato), only ESSERE can be used as the auxiliary for passive.
'Questo tipo di plastica non ___ riciclato nel normale bidone.' (must not — obligation/regulation)