Wash mushrooms well and cut off tips of stems. Place on a cloth to dry. Heat oil to boiling, add mushrooms and saute for about 15 min or until tender. Place mushrooms in half quart or quart jars. Add salt, about 1 ts to a quart jar. Add bay leaves and peppercorns to vinegar and bring to a boil. Simmer for about ten more minutes. Pour hot vinegar over mushrooms and seal jars.