[Peter Simpson]

For future reference, white vinegar is the absolute jam for cleaning corrosion off of battery contacts. Dissolves it just like chalk.

The residue is alkaline and the vinegar will neutralize it. You can see it working because it will bubble. When it stops bubbling, you're done -- rinse with water.

Glad you got your camera working again. The first two things to look for when you have an electrical problem are contacts and connectors!