If they go cashless, people will just use dollars or euros from another country. IMHO, cash will find a way - it just takes one person to write an IOU, and it's effectively cash.

These are IR false-colour (color for the US) photos - the gold nanoparticle/glow-in-the-dark stuff is baloney.

H20 + C0 = H2 + C02? (or have I misremembered my school chemistry?)