Normally, mushroom sauces are made on the basis of boiled mushrooms’ liquid. It can be made from dried or fresh mushrooms. Sort out and wash dried mushrooms several times in warm water. Pour cold water over them and keep for 3—4 hours. Boil in the same water until done. Take the mushrooms out with a skimmer, wash with cold water, chop fine, and use for sauces and soups. Strain the liquid and salt to taste.