Decorate the small paper bag with a scarecrow face. Use precut construction paper pieces cut in shapes, such as triangles, half-moons, circles, squares and rectangles. Glue the shapes to make a face, and allow them to dry.
Stuff the small lunch bag -- the head of the scarecrow -- half full of newspaper. Twist the bag and wrap the yarn around the twisted part. Tie the ribbon into a bow. Use strips of yellow construction paper for the hair of the scarecrow.
Use the medium lunch bag for the body of the scarecrow. Decorate with construction paper, using colored construction paper for a shirt and round pieces of construction paper for buttons.
Open up the body of the decorated scarecrow. Cut a hole in each side to fit the paper towel roll, which will be the scarecrow's arms. Preschoolers may want to decorate the arms before putting the towel roll through the bag. Stuff the body with newspapers, leaving enough room to twist and tie the bag with yarn.
Glue the head of the scarecrow onto the body. Decorate the gloves with glitter and glue. When they are dry, attach a glove to each of the arms of the scarecrow. When everything is dry, carefully insert the wooden dowel through the body of the scarecrow.