Preheat oven to 350°. Mix oatmeal, brown sugar, flour and salt. Stir in melted butter, then add egg and vanilla and combine well. Arrange batter by 1/2 teaspoons 2 inches apart on ungreased cookie sheets. Bake until lightly browned, about 5 minutes. Cool slightly, removing cookies from cookie sheet as soon as they are firm. Makes about 60 cookies.