Discard any tubers that float in a dip, because they will not keep. Have a small container of water nearby to wet the pencil. One indelible pencil should mark tubers from more than 100 clumps. Since indelible pencils are toxic, never put the tip into the mouth. The easiest method to mark tubers is to write the name of the variety.
Some commercial growers write or stamp a number for each variety.
After cutting, dipping, and marking the tubers, let them dry. Expect to let the tubers dry for about 24 hours for small roots and 24 to 36 hours for medium to large roots. Drying time varies depending on temperature and humidity. Do not dry the divisions on cement, because cement tends to draw out water and promote shriveling. Anyone unsuccessful in working with an indelible pencil can still use a thin indelible marker to name the tubers once they have dried.