How to clean car battery cables?
The Family Handyman says:
"First clean the top of the battery and any corrosion from the cables using a tablespoon of baking soda, a cup of water and a nonmetallic brush. Flush with cool water. Now disconnect the cables, starting with the negative one to prevent your wrenches from arcing on a nearby ground. Loosen the battery cable clamp bolts and gently give them a twist. Use a cable puller if they're stuck. Never pry on the battery posts. If you have a side post terminal, use a 5/16-in. box wrench to loosen the cables. With the cables removed, further clean off the corrosion around the battery terminals and cables with a post cleaner."