This may seem simple, but a lot of people do not know how to do it properly. Severely corroded terminals can cause poor electrical connection which can prevent the car from turning over/starting.
Materials needed:
Baking Soda
Wire Brush (Stiff)
Warm Water
Paper Towel
Screwdrivers or Wrench depending on how your battery terminals are fastened on. Clean Your Battery Terminals Crimp Crimping Auto Repair
Baking Soda
Wire Brush
My dirty battery. (Not really that corroded, but dirty.)
Step 1: Remove any kind of safety fastening you may have on your battery. My car uses a metallic strap kind of device to hold it down. It required me to remove 2 10mm screws.
Step 2: Unscrew/unfasten the terminals. Again, this varies. Always disconnect the negative (black) terminal first, then the positive (red) afterward. When you have these removed, go ahead and remove the whole battery from the engine bay. Set it down somewhere where you can work on it.
Tip: Avoid putting it on your driveway. Baking soda leaves an ugly white stain and it is hard to remove.
Step 3: Obtain a wire brush. These can be found cheap at home depot, and most people have them at home. It should be the very stiff kind.
Step 4: Mix 2-3 Tablespoons of baking soda with a little water. You don't need a lot of water at all, and really you shouldn't use a lot since baking soda isn't soluble in water anyway, it just floats in it.
Step 5: Pour a little of the water/baking soda mixture on both terminals on the battery, and anyplace else on the battery that is corroded. (Fastening contact points). You should hear a "Psssst" sound. With the terminals wet, scrub away at them with the wire brush. Scrub hard, they should practically shine after you're done with it. Wipe the excess water/baking soda with a paper towel.
This is what my terminal looked like after I was done:
Step 6: If your terminal connectors are not detachable and are still in the engine bay, pour the baking soda solution onto a towel and wipe the terminal connectors down. The towel should be very soggy though. Scrub away at them with the wire brush. If your terminal connectors are removable, do the same thing just take them out and you can pour the baking soda solution on them. Wipe them dry.
Dirty terminal connectors:
Clean terminal connectors:
Step 6: This is optional, but it should be done. If you have a petroleum based grease handy, smear the terminals and the terminal connectors with it. This will prevent corrosion (a little).
Step 7: Put everything back together. This time, connect the positive (red) terminal first, followed by the black (negative).
There, you're done.
