My dog has been vocal for most of his life, and nothing I have tried has worked; including training (both reward and punishment), keeping him inside (he still barks at almost anything), and I have even tried using a citronella barking collar, which didn't do anything for the barking, he'd only eventually get annoyed at the collar and attempt to "scare it away" by barking at the spray. He has always found something to bark at, whether or not there is actually something there.

As I have said, the collar is a last resort, and I really don't want to use this improperly. He is primarily an outside dog, and I am away for most of the day, generally between 7am and 6pm.

I know this is considered inhumane, and I hate the thought of hurting my dog, but I need to stop, or at least reduce the amount that my dog barks.

So how should I use this collar?