katyaker did you happen to save the pieces of the tuber neck? I've had success resurrecting just the sprouting eye with a bit of the neck material, when a tuber has failed to sprout roots, or if the body of the tuber has aggressively decayed but the neck is still seemingly unaffected. Doesn't work all the time. Most times I use a bit of rooting hormone powder. Keep moist, sprinkle with cinnamon to deter fungus. Provide a humid environment with good light.
Bottlecaps for a "pot". These were done for the fun of it.
This was done out of hopefulness. First time splurging on an expensive $40 tuber... and the body started to aggressively decay. These circled sprouts/eyes with neck material attached, were salvaged a few days ago.