
Postage due stamps
Czechoslovak postage due stamps were used to collect insufficient postal fees. The category includes classic and later surcharge issues used throughout the postal system.
Czechoslovak postage due stamps are a key element of postal regulation history.
Postage due system
These stamps were applied to underpaid mail and reflect standardized postal fee enforcement.
- classic postage due issues
- surcharge and numeral designs
- postal regulations
- important postal history usage
A fundamental collecting area of postal administration.

























