Do they ever stamp the stamps on mail in the US ?

Question

I've received mail from the US (international) and they never seem to stamp the stamps so they could easily be reused?

Does this happen only for air mail or even for normal post in the US?

Answer 1

The mail I received had their stamps stamped.

Answer 2

It is supposed to go through an electronic machine that cancels it. A scanning device like the ones used in department stores.

Unless you request that it be hand stamped, in the case of a musicial card or photos....thank you

Answer 3

Reusing a stamp is a federal offence.

It's not worth it.