Flaky mic in TDD built in phone coupler - sources?

[jpero at sympatico.ca]

This is round 5/16" dia mic with felt screen stuck over the small 
opening.

Now mic working intermittently and had to tap even bang on it to 
wake up.

Now today, I'm planning to combine my mic search with downtown 
shopping,  will these mic robbed from cheap headphone with mic with 
1/8" jack work?

Cheers, Wizard