In small saucepan over low heat, melt 4 oz. (4 squares) semi-sweet chocolate, stirring constantly until smooth. With spatula, spread melted chocolate in thin layer on cookie sheets. Refrigerate just until firm but not brittle, about 10 minutes. Using metal spatula or pancake turner, scrape chocolate from pan, forming curls. (Chocolate curls will be as wide as spatula.) Transfer curls to plate with toothpick. Refrigerate or freeze until ready to use.