My little guy did this in our rental apartment, and now we are having to sand the baseboards before we move out. I'm moving to a rental house until my house is built, so I would hate for him to do this again. They tell me that they do this sometimes out of "Boredum" ? If they are home alone during the day? What is the bitter apple thing, I need to get whatever it is so that I could spray it on to this new place we are moving into before he starts doing it there.