Trust me, he'll still want to eat bad things, especially when your not looking. Dobby loves soap, tooth paste, anything that is similar to food but bad he has to try so be careful just in case. So far he hasn't got soap or toothpaste poisoning in my or Momazons care but that hasn't stopped him from trying
He's like the scene in a Christmas Story where little Ralphy comes up to the door with a cane and dark glasses and they ask him what brought you to this lowly state, he answers it was soap Poisoning as his parents wail in the background and his dad tells mom I told you not to use Life Boy...