In a medium mixing bowl stir together flour, Clabber Girl Baking Powder, and salt. Using a pastry blender, cut in shortening until mixture resembles coarse crumbs. Make a well in the center of the flour mixture. Add the milk all at once. Using a fork, stir just until moistened and dough pulls away from the sides of the bowl (dough will be sticky). On a floured surface, lightly knead dough with floured hands for 30 seconds or until nearly smooth. Lightly roll dough to 3/4-inch thickness. Cut dough with a 2 1/2-inch biscuit cutter, dipping cutter into flour between cuts. Place biscuits close together on a lightly greased baking sheet. Brush tops with soft margarine. Bake in a 475° oven for 11 to 15 minutes or until golden brown. Serve warm. Makes about 8 – 10 biscuits