What can you substitute for whole milk?

evaporated milk mixed with equal parts water.

Reconstituted powdered milk.

Soy milk.

There are probably others but it would depend on what you plan to use the milk for and why you want a substitute. If you just don't want the milk fat, use skim milk. If it's for a recipe where the milk fat is needed for the recipe to work, there might not be a substitute.