In a bowl, beat egg whites until foamy. Sprinkle with salt and cream of tartar; beat until soft peaks form. Gradually add sugar, beating until stiff peaks form, about 7 minutes. Drop by teaspoonfuls onto ungreased foil or paper-lined baking sheets; sprinkle with the crushed candy. Bake at 225° for 1-1/2 hours. Turn off heat; leave cookies in the oven with the door ajar for at least 1 hour or until cool. Store in an airtight container.