Blue Battery corrosion on vehicles battery terminals is usually caused by the battery getting overcharged either due to the alternator or something else in the vehicles electric system.
If you get constant blue corrosion on your vehicles battery terminals it would be a good idea to have the charging system and electrical system checked out.
You can use baking soda and water mixed together and pour it on the battery terminals which will clean off the corrosion.
After you let the baking soda and water sit on the battery terminals you can then use a garden hose to rinse the corrosion off the battery.