Modern electrolytic caps don't burn like they used to. The last few times I made a mistake, there wasn't even an explosion, even less a short-circuit. The thin

Modern electrolytic caps don't burn like they used to. The last few times I made a mistake, there wasn't even an explosion, even less a short-circuit. The thing slowly boiled and bubbled or unfolded. Anyway, it blows up because the capacitor's insulation layer isn't some stable material, it's a tiny oxide layer built over the metal plate by anodization. If you put a high voltage on it with the wrong polarity, you reverse that anodization and short the liquid and the metal electrodes.