Baking soda works, so does coca cola actually, it does a very good job cleaning terminals. As Ken said get the felt washers, and/or some terminal treatment. It comes in a small spray can and is like a heavy paint, works well to keep the terminals clean for a long time.
Seems like a lot of corrosion for a car not very old, how does everything else under the hood look?
The artist formerly known as SteedaMatt.