I have heard that getting MSG works too. I think that is the main ingredient in those powders you can buy for that.
Wookie
did that when he was still having accidents in the house. The powders didn't help. I finally realized that he was doing it to hide the evidence of having an accident. Once he finally got completely trained to go outside he didn't touch it anymore. He won't mess with it all outside. Now he DID have an accident in the house last month when the ground was covered with ice and he wouldn't go to the bathroom outside. He didn't eat it, but he took it and hid it under the bed in the guest room!! LOL