Koehler methods were probably the most harsh.I really like setting things up so they get "caught in the act," even when I'm not there. I think it was the Koehler book that taught me how to set up what I now call the "Trash Monster," with an empty soda can with some dried beans in it and a length of dental floss, thread or fishing line tied to, say, a hot dog in the otherwise clean kitty box. The can should be perched above the box, ready to pounce as soon as the pup grabs it. This works on anything you want to teach pup not to grab. It doesn't have to be a hot dog. Use imagination! It usually only takes once!