"jim evans" > wrote in message
news
>
> I've never seen this before. My battery has built up a lot of
> corrosion, but under the hold-down. Not on the terminals.
>
> http://tinyurl.com/v5xr9
>
> What would cause a battery to corrode in this odd location, but not at
> the terminals?

Thats from the gas expelled by the battery. It's eating the metal in the
hold-down.

Take it off. Clean it good... some sanding, etc. and give it a good coat of
rust paint before re-installing.