I never thought about that.
But the only way the russian mattress hoards of US currency can do harm to us here in america is if all those dollars find their way back to US soil. I’m not so sure that will happen. besides, the total value of those mattress hoards are insignificant compared to the digital dollars given away to banks and others here in america.
I saw a map on TV of the dollar as the savings currency about 3 years ago, it dwarfed all of this because it has been going on since WWII, It is trillions upon trillions of dollars.
Not only that, lots of it is counterfeits mixed in with legit bills with dates going all the way back to 1958.
The location of U.S. currency: how much is abroad? - survey methods indicate 55% to 70% of all dollars located outside country - includes related articles
http://findarticles.com/p/articles/mi_m4126/is_n10_v82/ai_18786211/
Chart of US Money Supply, everyone focuses on the last few years, but most of this money was tied up to a certain degree in the banks,
Now look prior than the last few years, yes, we had inflation but no way near what we should have in the Carter Years, much of this was socked away behind the iron curtain and all around the world for their savings.
If the dollar starts to crash, all these dollars will come home to roost.
http://www.chartingstocks.net/2009/03/chart-of-the-us-money-supply-1917-2009/