fetchmail + postfix

Hi, I have a client's mailserver that uses fetchmail to download mail from a global mailbox, hands it to postfix to redistribute. Mail with invalid to: fields gets bounced, but not deleted from the global mailbox. I have tried various things to delete those mails, but no luck so far. What is the correct way to have fetchmail delete bounced messages. Or to have messages with invalid to: fields be diverted to one local acount, say postmaster? Thanks -- Kind regards Hans du Plooy Newington Consulting Services hansdp at newingtoncs dot co dot za