[denisond3]

Two things I do, and never have that powdery corrosion problem:
With the battery cable disconnected from the battery, I always scrape the outside of the battery post, and the inside of the terminal, very lightly with a penknife or exacto knife. This knocks off the lead oxide that naturally forms on the lead surface, and lead oxide does not like to conduct electricity. To get rid of the powdery blue you have now, take the battery cable off and soak it in a cup with water and baking soda dissolved in it. Give it a good 30 minute soak, then rinse it off with water and let it dry.
Also, wash the top of the battery with water. It wont hurt anything, and will rinse away the dried electrolyte that always collects on the top of a battery from normal outgassing.

Incidentally - when you disconnect the battery, always start with the negative terminal. That way if your wrench comes in contact with some metal of the car - there wont be any spark and no damage. Then when undoing the positive cable, the battery's negative end is already disconnected - so there wont be a spark and no damage will occur.


As to whether you need a new battery I cant say. If its more than 4 years old, it has pretty well paid for itself. If its more than 5 years old - then you are pushing your luck.