Chocolate that has ingredients like animal fats or alcohol is haram. If alcohol is used to clean the machinery that makes the chocolate bars, then that chocolate is also considered unfit for consumption for Muslims. If the glue used in the packaging is derived from animal fats, that also makes the chocolate haram. For chocolate to be classified as halal chocolate, not only must it not contain unlawful ingredients, but it cannot be processed or stored or transported in ways or facilities that are haram.