Another option is to make the dollar inherently valuable via nanoparticles of silver embedded in it, to the level that its worth approaches believable value. Given silver's future, this would mean hoarding of dollars,or savings, would reappear.
Also, the dollar would be then bacteriocidal, which would be beneficial for public health. People could conceivably clean their hands with their dollars. Probably the matrix material would have to change also.
I have way too much time to play with lately.