Only the heads of the mushrooms should be preserved.
(The stems can be used up in sauces.) Do not peel the mushrooms.
Let them steep only for an hour in fresh water and mild or wine vinegar.
Then put them into boiling water with a dash of vinegar in it.
Bring the water to the boil again, and boil for 2 minutes.
Take them out and drain them.
Then soak the mushrooms for 2 hours in cold water, and drain them again.
Now they are ready to be arranged in layers in the preserving jar, or jars.
Each layer must be very lightly sprinkled with salt.
Cover with vinegar.
After 24 hours steeping like this, the mushrooms must be drained, and then put back in the jars again, to be covered with boiling vinegar to which you have added herbs or pickling spices.