I recently noticed that there is a [pmpd~] object that lets you make
a physical model that runs at audio rate, so I suppose you could make
a little model of a mass that rattles against another mass when
excited by the input signal and have that interaction trigger a
proportional click with a little reverb maybe that would sound like a
bottle cap.

Collin

I m trying to make a patch for my guitar that would simulate the
buzzing sound of beer bottle caps on mbiras