BackyardBouquets_17 if it was my tuber I would remove the sprout** as one would for taking a cutting, and trying to leave any remaining buds on the tuber. I would rinse off the one inch cutting, then place in about 1/4" of water in a bottle cap or vessel that will allow the cutting to remain mostly upright. I'd place in indirect very bright light, and when possible facilitate the water it's sitting in being warm. Crazy people like me move it around to different window sills. Keep the water level maintained, and replace if it gets dirty. I've had luck with rooting this way(takes 10 days to 21 days), when all else has failed. It just is a matter of how much fiddling you have time for.
** I am actually doing this activity this morning on a variety I really want to save!
