Have you ever waited for that queuemessage to be available again? I have.
Well here is your dirty fix for that. (during development atleast)
Using the Azure storage explorer, you can find it here.
Connect to the storage in question, select the queue that is messing with you.
Add an empty message to the queue, then click the button "Clear queue".
Voilá an empty queue.
Watch out for using this in other ways than development. It really clears all the messages.