In the process of "candling", a hollow candle is put in someone's ear and lit. Which is supposed to create a vacuum to draw out excess wax and "toxins". It's also supposed to clear out your sinuses. And the wax and "toxins" are supposed to be burned by the flame, once drawn out.
Except that it's just a bunch of nonsense. There's no way that anything, especially ear wax, can be drawn out of the ear by creating a negative pressure. If the process in fact succeeds in any measure, it is more likely to rupture the ear drum.
The sinuses are connected via the inner ear and you regulate pressure there all the time. If a negative pressure drained anything out of the ear, we'd all have draining ears on airplane flights. Eww.