Originally posted by Dan
Disconnect battery. Mix some baking soda with water, and using a brush scrub everything clean and rinse. Let dry and reconnect battery. Some autopart stores sell anti-corrosive pads that fit between the battery and cable that work well to prevent this from happening again.
That green stuff is what happens when battery acid and copper mix.
The seal around the battery post could be "weeping" acid. The only real fix is to get a new battery.
Yes, the pads from "Sears" (those ones filled with red goop) work great for a while. However, some "brutes" like to "wail" on the battery terminals and this breaks the case around the battery posts. The acid keeps coming and coming and it gets pretty expensive to replace the wiring...