There is nothing that you can soak potatoes in to eliminate viruses. The viruses live inside the cells. It might reduce the odds of introducing certain kinds of fungal pathogens, but even most of those penetrate fairly deeply into the tissues.
Grocery store potatoes are likely to carry viruses and organic types virtually certain to, but this probably only matters to you if you are also growing potatoes that you value and have managed to keep virus free. The common viruses will reduce your yields, but if you aren't also growing healthy potatoes, you might not notice the difference for a few years.
My PEP Badge Tracker: An easier way to track your PEP Badge Progress