The vinegar sounds good. You'd probably need a whole lot of it.
If it were me, I'd soak them in muriatic acid (HCl) from the hardware store until they stopped fizzing. However, I'd be using hand, eye, and lung protection in a well ventilated area, with plenty of water handy and a couple of boxes of baking soda in case of inappropriate contact. Disposal with plenty plenty plenty water. HCl isn't all that bad, they use it to clean concrete and hose it down when done.
You could use sulfuric from the car parts store (used to be for replenishing the battery acid in batteries) but it's pretty expensive and I don't like the fact that even diluted, if it contacts something, the water will evaporate away and leave the con acid to etch its way around. Usually on clothing, where mysterious holes appear some days later. It's not the worst or strongest acid around, it's just untrustworthy.
With any acid, its strength wiil be at least partially diminished after the reactions take place.
The mist generated by the bubbles will contain the acid.
These reactions generate hydrogen gas, so no ignition sources nearby. "Well ventilated." Hindenberg.