The car battery on a Subaru has certain hazards that should be understood. The battery is a lead-acid type, which uses sulphuric acid as a medium for activation. Sulphuric acid causes physical harm if it comes in contact with skin. When it is being charged, it gives off a gas that can be harmful to the mucous membranes in the nose. The battery should never be tipped. The white-appearing corrosion around the battery terminals can cause acid burns on the hands.
Lift the bonnet of the car. Wet the battery terminals down with a little water.
Shake some baking soda on both battery terminals and allow it to work for a few minutes. The baking soda is an acid neutraliser. The baking soda on the terminals foams up with a greenish colour as it works. Wash the terminals off with water and apply more baking soda until the terminals are free of all corrosion. Wash all residue from the top of the battery before removing the battery. Use the baking soda on the battery hold-down clamp as well.
Loosen the bolts on the negative and positive cable terminals with a wrench. Remove the negative terminal first. Use the pliers to twist the terminals to pull them off.
Loosen, then remove the nuts securing the battery hold-down clamp. Remove the hold-down clamp. Lift the battery out of the vehicle. Clean the battery seat with baking soda to remove the corrosion and prevent metal deterioration.
Place the battery back in the vehicle and install the hold-down clamp. Install the cable terminal on the positive battery post, followed by the negative. Coat both terminals with a light coat of grease to prevent future corrosion.