
One response:
Stamps, like money, are obligations of the issuing state. Like
banknotes, you can possess them as though you owned them (with a few
restrictions - like prohibitions on defacing them), but you can't own
them. That wouldn't apply to private carrier's stamps. Like
software - you "buy" it, you can "use it", you can even toss it out
(or like coins, melt them or otherwise destroy them). But, you can't
own it if the real owner / creator / issuer is only willing to license
it to you.
Some countries "demonetize" them - i.e., abrogate the contract they
represent... I guess then, maybe, you could "own" that which the state
has declared to be worthless and essentially abandoned.
Remember the old adage "possession is 9/10ths of the law"? It
represents less than the perfection of ownership. Guess what the
tenth tenth is.
Len Nadybal
Washington DC