This is the only remedy that really works. Reliably.
Because while other suggest warm water and baking soda, or using a debriding agent like a salicylic patch, these don't work. Those methods may soften the skin sufficiently so that you can remove the splinter a bit more easily, but they don't actually cause a chemical reaction that causes an embedded splinter to move towards the surface of the skin Much as those who rely on the warm water/baking soda aver, there is no chemical reaction going on there. It's inert.
With vinegar/peroxide and baking soda, there is a chemical reaction. That initial bubbling reaction that you get may stop, but the interaction of the two ingredients that causes that initial bubbling? That continues to work more subtly on the finger. And, after about twenty minutes of soaking, the splinter will move closer to the surface of the skin. And it can then be painlessly, and I do mean painlessly, removed with tweezers.