Once in a while I get mails reused by certain servers(like AOL). After this happens too many times I might want to delete the deferred mails still stuck in the outbound queue.
First I try again to send all the mails stuck in the outbound queues by issuing the command:
postfix flush
Then delete the outbound mails that still got refused by the picky server by issuing the command:
postsuper -d ALL
It is not the most elegant way to solve this situation but for now it cleans the stuck outbound mails.