Buttermilk
You only want to use this substitution for baking with buttermilk! Stir in 1 Tbsp. lemon juice to 1 cup milk, let it sit for about 5 min and the milk will be soured and ready to use in place of buttermilk.
Ketchup
1 cup tomato sauce, 1 tsp. vinegar, and 1 Tbsp. sugar
Sweetened Condensed Milk
¾ cup white sugar mixed with ½ cup water and 1 ⅛ cups dry powdered milk: Bring to a boil and cook, stirring frequently, until thickened, about 20 minutes.
Margarine
1 cup shortening plus ½ teaspoon salt
Using Flax Seed as a Substitution
At Costco I found a product called “Cold milled flax seed”. You can substitute this ground flax seed for oil, butter, and egg. It is a good back up for your food storage. I have made bread, waffles, and pancakes and I can not tell a difference. On the outside of the container it will tell you how much to substitute for. Flax seed is also very good for you, it has a lot of omega 3 which is the healthy fat in fish and which is why fish is so good for you.