The City (contact Clean Cities from the city's website) can advise the private property owner of the best method to remove graffitti but is not allowed to remove it from private property. It should also be reported to the police as it is reported as vandalism. They police have a good record of arresting the perpetrator as they often brag about it or have a characteristic writing or symbol. It should be removed as quickly as possible to deprive the jerks of any lasting message.