I have no problems exchanging IRC's at my post office. As a matter of fact last summer they received a bulletin from the Post Master that all IRC's that are validated by a US Stamp (originator) are to be redeemed for 1ドル.15. (not .80 cents, foreign ones are still redeemed at .80 cents. `) So if you have a IRK that started in the US demand 1ドル.15