Sacrificing a scrap EMI shield from a junked PC as the electrolysis anode, I grabbed a tab with the battery charger clamp:

Turns out it didn’t survive the encounter:

That white blob extends around to the other side:

Yeah, it got hot enough to melt a blob from the 6 gallon plastic bucket before burning through.
I tossed that into the garage so I wouldn’t forget it aaaand here we are …