Does anyone know how to remove the left hand thumb rest? yes, the little round plastic in black. thank you guys in advance!:bighug: Mine is a yamaha sax

Hello all, Some of my needle springs have developed a fine fuzz of rust. I suspect this is because of 'condensation' dripping out of the middle C tone hole (and nearby tone holes) onto the springs below, and I'm so far too much of a newbie to have picked up on this earlier to prevent it...