Muriatic is same stuff as battery acid, different concentration.......hydrochloric. Also, we used to use it to clean water-to refrigerant heat exchangers, "coil clean" I still have some it. THAT last stuff is pretty concentrated, and you want to be careful
Back when we had "real" auto parts stores, many carried battery acid, and if you had a container you could buy a little, or with a little more money, buy a container. They came in different sizes, don't remember. Seems like the smaller was about enough to fill a dry battery, and the larger container was maybe a couple? gallons.
And back when we had "real" chemical supply houses, ----and they weren't worried about registering and licensing every damn thing, they could also sell you various types
