When your dog steals something do you chase after him trying to get it back?
Don’t play this game of chase anymore. You are reinforcing an unwanted behaviour. The more attention you give him for stealing something, the more he’ll steal.
As long as it’s not dangerous ignore him when he steals something, he’ll stop pretty soon if there is no reinforcement involved. Write the incident off to your mistake, as you are the one who left it lying around in the first place. Remember prevention is better than cure.
Make sure he can’t get to items, which are off-limits. Keep tables and counters completely free of food and other fun chewables; keep the laundry out of your dogs reach for several months until he no longer looks there for fun. He is stealing this stuff to entertain himself so rather have plenty of yummy chew treats to keep him busy and make sure he is getting exercise and his mind is being stimulated with fun games. If your dog has stolen something you need to take back. Don’t just take the article from him this will only teach him that when he has his fun toy and you come towards him, his fun is going to stop and he will begin to hide with his stolen items. Instead offer him something much better a great big yummy chew toy, not only will he drop the stolen item for you to get back but he will be occupied with this new yummy treat and he will completely forget his stolen item. This will also make him happy when he sees you approaching because good things come from you.
Reference: (page (110)
The new dog owner’s guide to Positive reinforcement puppy training – Suzanne L. Harris