Premodern states would do this all the time. A ruler would find themselves strapped on cash, debase the (metal content based) currency, people slowly find out, raise their prices, rinse and repeat. Gresham's law (https://en.wikipedia.org/wiki/Gresham%27s_law) states that when 'pure' and 'impure' coins are both in circulation, the impure currency takes over.