“Does it work” has three different answers depending on what is blocking your speaker. Here is each one, without overselling.
For a complete overview, see the complete guide to water ejection.
Works reliably: water
This is the strong case. Water in a grille is held by surface tension, which has a breaking threshold —
enough repeated diaphragm displacement exceeds it and the film fragments all at once. That is why water
often clears in a single cycle. Apple uses the same principle in the Apple Watch water-eject feature.
Works partially: dry dust and lint
Loose particulate comes out well. Interlocked textile fibre comes out gradually across four or five
passes, and some of it does not come out at all. Combining acoustic cycles with exterior brushing and
adhesive putty closes most of the remaining gap. Expect substantial improvement rather than a complete
restoration on a months-old blockage.
Does not work: adhesive contamination
Oil, earwax, dried sugar and fibre that got damp and set as it dried are held by adhesion rather than
resting mechanically. Vibration applies mechanical force, and mechanical force does not break an adhesive
bond. No volume changes this.
Does not work: hardware faults
A torn diaphragm, a corroded contact, a failed amplifier, a disconnected cable. Sound moves
obstructions; it does not restore components.
How to tell which you have
Blockage sounds muffled but complete — quieter and duller, nothing missing, nothing rattling.
Buzzing that worsens with volume means a torn diaphragm. Total silence means a broken connection, because
blockage produces quiet and never silence.
The honest stopping point
Three cycles. If nothing has changed audibly by then, the mechanism is not engaging and further cycles
will not make it start.