FREE: 1980 GUINEA - BLOCK OF 4 - FIRST MOON LANDING (20) - MNH

CTO is especially common in countries that try to make money from collectors by issuing large numbers of topical stamps. To make more sales, the stamps must be inexpensive, but if the issuing postal service prices them below face value, commercial mailers could use them to save money by routing their mail through the issuing country, financially hurting the issuer. So these countries issue most of their collector stamps as CTOs. It is easy to recognize such stamps. The cancellation is neat, usually in one corner without a town name, and the gum is still present.