IRCs are no longer for sale in the US.

"As of January 27, 2013, the U.S. Postal Service no longer sells international reply coupons. Coupons previously sold by the U.S. Postal Service may no longer be used or exchanged." (http://pe.usps.com/text/imm/immc3_020.htm}

You need the stamps of that country from where it's being sent for postage. Period (e.g., a letter from the UK needs British stamps, not US.) Or send the person money to pay for postage from their country.

Wikipedia is a great starting point for research, but you need to verify what's on there as anybody can edit or make up a Wiki entry.

What section are you reading to make that assumption?

Sorry you're totally wrong.

Most of the information in that article is historical and not current.

IRCs for example, the mainstay of the UPU, are no longer for sale in a number of large countries such as UK&USA.

You can try getting USPS to accept another countries stamps as payment, they'll just RTS to the celeb or throw it in the trash.

https://en.wikipedia.org/wiki/Universal_Postal_Union

If im reading this right you can use your own counties stamps for any overseas return postage. No need to keep buying US stamps for me.......