Hacker News new | past | comments | ask | show | jobs | submit login

According to https://en.wikipedia.org/wiki/Event_cover they are "decorated, stamped and canceled commemorative envelopes"

Essentially they are envelopes with stamps and a marking over the stamps that prevents the envelope and stamps to be used.

https://en.wikipedia.org/wiki/Cancellation_(mail)




Applications are open for YC Summer 2020

Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | Legal | Apply to YC | Contact

Search: