I received a clarinet in for repair today, nothing unusual.  I did find something regarding the mouthpiece that bothered me and thought I would share it as an example of what not to do.

After you finish playing your clarinet you should swab out your mouthpiece just like you do the clarinet.  You should NEVER use any type of swab that is made out of cotton and that is fuzzy. (A better choice would be a pull through silk swab.)  Using cotton can lead to excess lint build up in the clarinet.  In the pictures below a cotton swab was used and left inside the mouthpiece.  NEVER leave a swab inside an instrument or mouthpiece after swabbing, this only traps the moisture inside instead of letting the instrument dry out.

In the second picture below you will notice the swab has metal ends.  These metal ends are sharp and as you can see have scratched the inside surface of the mouthpiece.  This is a sure fire way to destroy a good mouthpiece.

Never use swabs made from cotton, Never leave a swab in an instrument or mouthpiece, Never stick anything in an instrument or mouthpiece that can scratch!