Cream margarine, oil and sugars with mixer. Add eggs and vanilla and beat well. In separate bowl, sift flour, cream of tartar, soda and salt together. Add mixture to creamed mixture and blend well. Chill dough in refrigerator a minimum of 2 hrs. Put tablespoon size dough balls on greased cookie sheets. Return remaining dough to the refrigerator. Decorate with colored sugar. Bake in preheated 350ºF.  oven 10-12 minutes or until cookies have a brown rim.