Battery terminal corrosion on 2005 Mercury Montego

Postive battery terminal corrosion cleaned month ago.
Corrosion returning.
Why?

1 answer
The battery probably has a small leak, possibly around the battery terminal. I would consider replacing the battery. Also, when you clean a battery, clean the entire battery with an acid neutralizer (baking soda) and remove both terminals and clean the posts and the cable ends.