Devise a lesson that focuses on teaching children what "personal property" means. This should be a key component to any lesson you prepare on vandalism, which includes places vandals often graffiti, such as school grounds or neighborhood houses. It isn't necessary to give legal definitions, especially when explaining these ideas to young children, but it is important that children understand that vandalism is wrong, from an ethical point of view, as well as against the law.
Offer comparisons and examples that will help children better understand the concept. You can use something a child considers "his" or "hers" to demonstrate your point. For example, use a favorite toy or game to demonstrate what "personal property" is and that only by asking can someone else play with that toy or game.
Give children alternatives for expressing themselves. Some cities, schools and colleges have chosen to deal with graffiti problems by providing a compromise for those that may be considering vandalizing public or school property. For example, North Carolina State University offers students the opportunity to add graffiti to tunnels that connect two sides of its campus.