Pour whole milk into small sealable freezer bag and add vanilla extract, sugar, and sweetened condensed milk. Seal bag well, and make sure there are no leaks!
Scoop about 1 cup of finely crushed ice (or powdery snow) into large sealable freezer bag and sprinkle with good amount of salt. Put small freezer bag with ingredients inside large freezer bag, adding more snow and salt on top. Seal large bag well.
Knead with your hands to combine and freeze ingredients, adding more ice and salt as needed. Keep kneading until an ice cream consistency is reached, then scoop out a spoonful and taste!