GRamaley,
Dormant cuttings do not require any additional moisture for storage or shipping.
Excess moisture may contribute to molding prematurely, if storage temperatures are too warm.
Sealing the cut ends and storing with a small amount of Dessicant (I use 1-2 tablespoons of dry shredded long fibered sphagnum moss per 1 gallon storage bags) has resulted in a very high viability rate in my experience (over 98%). Also IMO, washing is not necessary for storage.
Good Luck.