Preparing Your Car for a Battery Change
First and foremost in preparing your car for a battery change is ensuring that the battery isn't receiving any power from your engine. You may have found that your battery needs replacing after it failed to turn over, so your keys may still be in the ignition. If so, remove them. Without the keys, your car's electrical system shouldn't be active, which will reduce the chance of a spark or shock while you're changing your battery.
If you've already brushed on the baking soda and water solution to the terminals, you're ahead of the game. If not, go ahead and clean the terminals as fully as possible. Removing the sulfate deposits should make it easier to unscrew the nuts from the bolts on the cable ends and from the posts. Gently knock the posts and cables with your hammer to break up the deposit. Then brush on the baking soda solution and finally wipe it away with a rag.
Once the battery is cleaned, inspect it for cracks where acid might escape when you remove it. Make a mental note of these places so you can avoid placing your hands near them during removal. You might also want to place duct tape over any cracked areas to provide a layer of protection — albeit a minimal one.
Lay your tool container on the ground or position it in the engine bay. Just be sure not to place it on a hot surface where it can melt. Avoid a metal toolbox, as it could potentially contact the battery and spark.
Your battery is cleaned, you've searched for cracks and your tools are laid out. It's time to remove your old battery.