AirPods Microphone is not working

I have Apple AirPods 1st Gen. From last couple of days, my voice is breaking for recipient and most of the time they are not able here me or with distortion or breaking voice.

I have cleaned them fully with Iso propyl alcohol and cloth for sanitization but they are not working still.

I could not clean them and some zinc colour material is stuck into small patches of mesh , I think.

I have attached some live microscopic images of airpod meshes.

What are your thoughts?