Is it okay to use old potatoes that have grown sprouts if you cut the sprouts off? ~ Sarrit Kovacs
If the potatoes have sprouts and are soft then you should throw them out. If the potatoes are still firm but have sprouts, you can remove the sprouts and cook the potatoes. I find that sprouted potatoes are best when boiled and eaten plain or mashed. If you bake them they have a bitter taste.
~ Gloria Kobrin of Kosher Cookbook