Demystifying CTO (Cancelled To Order) stamps

Cancelled to Order/CTO US Back of Book Stamps for sale

How can I tell whether stamps are CTO - or not? - STAMPBOARDS - Postage Stamp Chat Board and Stamp Forum

Demystifying CTO (Cancelled To Order) stamps

Cancelled to Order/CTO United States Stamps for sale

Demystifying CTO (Cancelled To Order) stamps

Cancelled to Order/CTO US Back of Book Stamps for sale

Demystifying CTO (Cancelled To Order) stamps

Great Britain – a very rare postal notice, trial 2d sheet & 1d red rare cancellations

Cancelled to Order/CTO Worldwide Stamps for sale

Letter Writers Alliance: Stamp Information

East German stamps - could someone explain these cancels? - STAMPBOARDS - Postage Stamp Chat Board and Stamp Forum

Cancelled to Order/CTO Postage Stamps for sale

Thank goodness, they're all Cancelled-To-Order

Cancelled to Order/CTO United States Stamps for sale

Stamp Collecting Terminology: Cancelled-To-Order (CTO)