You cannot make evaporated whole milk by boiling away 50% to 60% of the water in 2% milk or skim milk. That is, you will not wind up with an evaporated milk that is around 8% fat. But you can certainly make evaporated low-fat or evaporated skim milk by boiling them down.

It is much less fuss, though, and probably a lot more economical, to pick up a can of evaporated low-fat or evaporated skim milk on your next trip to the grocery store. Each should be available in any well-stocked market and has a seriously long shelf-life.