1) Demonetize 2) Devaluate 3) Devalue 1) Demonetize 
to deprive of monetary value; to withdraw from circulation
demonetize, demonetise (British) 1. To stop using a particular metal to make coins. 2. To withdraw units of money from circulation. 3. To deprive (an issue of postage stamps) of validity by legal methods and without marking the stamps themselves.