The battery in your car doesn't make scary noises and it will probably never belch smoke. It rarely does anything until the day it simply stops working; which is probably why batteries suffer more neglect than most other parts. I'm as guilty as anyone: since we can’t service our batteries any more, I tend to ignore mine until time comes to replace it. Happily, other than being an awkward size and weight, batteries are pretty easy for the average car owner to change... easy, that is, if the terminals aren’t so corroded you can't get them off the posts.
The last time that happened was on my “classic” (at least according to the DMV) pickup, which hadn’t had a new battery in a decade and had only been started once or twice in the past year. I tried, but no way was I going to get the terminal loose. I headed to the auto parts store for a new tool, which turned out to be a Mechanix Choice Battery Terminal Lifter (#202501C). I plunked down about four and a half bucks (plus tax), took my new toy home, and in minutes had that battery removed and ready for exchange.
Terminal lifters like this are basically a strange-looking clamps that looks a lot like some corkscrews. There are two arms that slide under the stuck terminal and a crossbar-driven screw that rests atop its post. Turn the screw by hand; that pulls the arms together beneath the terminal. Once the arms have contacted the post, the screw action starts to lever the terminal up the post. You continue turning the screw until the terminal comes loose and detach the lifter, at which time you can remove the battery.
A good design for this tool would be fairly beefy, with a non-marring cap to prevent damage to the battery post. The arms would move smoothly, and the screw would turn easily. A quality terminal lifter might cost $25 to 35; my Mechanix Choice version cost less than $5.
As you might expect, this cheap terminal lifter proved clumsy to install and use, partially because it's made of poor-quality materials. That screw crossbar? it bent almost immediately. In fairness, the lifter did what I bought it to do: lift a corroded terminal.
A bunch of identical, cheap versions of the lifter are made in Asia and sold under different brand names (besides the Mechanix Choice 202501C you’ll also find the Super Start 08515, the Deka 859C, the Pico 0681, the FJC 46155, and the Great Neck 25121). No matter what the brand, it’s sold at a price of $4 to $9. All are made of soft, cheap steel or iron with zinc plating, and all have handles dipped in red vinyl. It will last for just one or two uses, meaning it’s essentially disposable. When you need one, you will likely find it around the battery display at your local auto parts store. Though more or less disposable, it still costs less than a new battery, which you’d need if you broke a post on one that’s still working, and it costs less than a new cable. Just be aware that you’ll probably have to buy another one next time you have a stuck terminal.