Felt material covered rollers are an option supplied in lieu of sponge rollers.  A rectangular piece of material is wrapped around each roller.  The moisture and direction of rotation keeps the material on the roller.

Drying of potatoes is very good.  It should be noted that if potatoes are too dry then there can be difficulties in the tubers flowing to weigh heads. A liitle moisture is required to maintain a good, smooth flow of crop through a pack-line.