Remainder Marks are no longer placed on remainders. Before the age of UPC codes and warehouse scanners, remainder marks were used to indicate that a book was remaindered and could not be returned. Now the books returned to publishers for credit are scanned as they are received and (so we are told) your account is not credited for those which you return after the remainder date. Hurts (see glossary here), not remainders, are marked. The mark is usually a black dash or line on the bottom edge of the book which can only be seen if you pick up the book and look. Some publishers use other marks. Random House marks its imprints and distributed lines with a red dot. Oxford University Press uses a small rubber stamped OUP in an ellipse. Almost everybody else uses a black marker.