Old letter and document collections can have value for a variety of reasons. If the writer is a famous person from history it is likely to have value. A letter or document might have value if it is about a historically important event or from a historically important place and time. An old document may actually have value for its stamp, though you may not see one (embossed).
Documents of all kinds may have revenue stamps. Some of these stamps are adhesives while some are embossed.
Additional letters and documents that may be of value are:
- Items from 1945 or older
- Old passports
- Stock certificates
- Folded letters (because of their postal markings)