Mashed Potatoes for 100

30 pounds potatoes (100 medium)
1/2 cup salt
1 teaspoon pepper
3 cups butter or margarine, melted
3 quarts hot milk

Peel potatoes, cut into small pieces, put in large pan and cover with salted water. Boil until soft. Drain off water, mash, and gradually add hot milk and melted butter, beating well. Beat in pepper. Add more milk if needed.