The new lawn mower battery works like a charm — the mower started up and ran as soon as I got the new battery in it.
As it turns out, battery acid eats right through cotton, given enough time. There’s a big ol’ hole in my T-shirt that started to unravel and tore all on its own. So far, my skin is not reacting to the battery acid any more than a light itch, easily ignored. But these shirts are rags now.