It is possible to impose that cash must flow, by replacing bills with stamped vouchers that lose their value if they are not stamped (change of hands) at a set frequency.
It is an "out of the box" tinkering with the velocity of money. Was tried locally in Germany during the great depression. Could be tried today, thinking big and using new "enforcement" technologies like e-wallets, e-cash, etc... Pierre
He proposed that international (centrally issued quasi special drawing right) "Bancor" trade balances would incur a charge on both positive and negative balances.
What we got was the US IMF/World Bank approach with the dollar as global reserve currency and giving the US a free ride to unlimited "seigniorage".
Worse than that, the fact that the interest charges are made only on negative balances has created a one way flow from poor to rich nations. This is a form of positive feedback that has ended up - which as mathematically it had to in a world of finite resources - in continual instability and, eventually, our current terminal meltdown.
My understanding is that the concept of "money that rusts" was that of Gesell, and that Keynes was a big fan of Gesell's. "Any economic unit can emit money. The serious problem is to get it accepted" Hyman Minsky
