This may be a clue " iraq, afghanistan, and various other ones"
Because some countries are now sanctioned by the US and Etsy is a US based corporation you cannot sell ANYTHING from those countries--whether new or old, spendable or not. I do not know all of the countries that are sanctioned but Cuba and North Korea come to mind. You cannot even mention the name of those countries in a listing, nor cities within--i.e., Havana, etc.
Check out what world countries are sanctioned (they get added to often) and you may have to pull any currency from those--even the old old stuff.
ETA: I did a quick google search and found this PARTIAL list:
- Afghanistan.
- Belarus.
- Burundi.
- CAR.
- China.
- Crimea.
- Cuba.
- DRC.
