Paying taxes in WTFs is easy. 


Simply print out the number demanded and send them to the taxman.


If your government refuses to accept payments in WTFs, and you live in a democracy, simply vote for a more enlightened government.  Politicians are sometimes a bit dozy and tend to forget who works for whom.


If you do not live in a democracy you should, with a medium sized printing press, be able to use your WTFs to purchase the overthrow of your government by a WTF-friendly power, or independent mercenaries.



Tip: Make sure your takeover forces don't double-cross you afterwards, revert to a monopolistic value system, and maybe kill you.