You could try taking "Tip Cuttings"
When I grew Dahlias and on the odd occasion they become virused (T
here's that word again ) we would take tip cuttings
Apparently the top couple of inches of new growth has yet to succumb to the virus so once rooted you have a non-virused plant.
Perhaps the system might work with Mint????
Probably worth a try....what have you to lose?