First, list your queues:
rabbitmqadmin list queues name
Then from the list, you’ll need to manually delete them one by one:
rabbitmqadmin delete queue name="queuename"
Because of the output format, doesn’t appear you can grep the response from list queues. Alternatively, if you’re just looking for a way to clear everything (read: reset all settings, returning the installation to a default state), use:
rabbitmqctl stop_app
rabbitmqctl reset # Be sure you really want to do this!
rabbitmqctl start_app