In a large bowl, stir together the milk, cream, sugar, salt, vanilla essence and peppermint essence until the sugar has dissolved. Colour to desired colour with the green food colouring, starting with just a few drops.
Pour the mixture into an ice cream maker and freeze according to the manufacturer's instructions.
After about 10 minutes into the freezing, add the chocolate chips. After the ice cream has thickened, about 30 minutes later, spoon into a container and freeze for 2 hours.