How to read messages in flight status and delete it by boto library

For testing purpose, I need to read the messages in flight and delete the messages in flight. I can't find a suitable solution so I use work around way now

to read messages in flight 1. stop message consumer process 2. wait for message is available and read it but not delete 3. start message consumer process

to delete message in flight (try clear() but it only delete message available) 1. delete queue 2. recreate queue

Any better solution?