Mix Carnation, sugar and chocolate in a saucepan.Bring to a boil over medium heat. Cook 5 minutes, stirring vigorously( Start timing when mixture starts to bubble around edges of saucepan). Remove from heat. Add vanilla. Beat with rotary type beater for 1 minute. Serve hot or cold on icecream, cake or pudding. ( If sauce is too thick when cold, add more undiluted Evapotated milk before serving.