Many countries are using polymer currency. The Bank of England recently issued polymer 5 pound bills (with plans for 10s and 20s).
Doug Maw (a vegetarian) started a campaign on change.org regarding the small amount of tallow in the banknotes.
The inventor of the notes thought the campaign was "stupid" since the amount was trivial and similar amounts of tallow could also be found in soap and candles.
To it's credit, the Bank of England listened and met with Mr. Maw, and decided not to withdraw the 5 and 10 pound bills, but maybe the 20s will be vegetarian.