Many compact disc changers in use in automobiles have moving parts to physically change the CD from one sleeve in the magazine to the next. Should the changing process take place during a sharp jolt applied from a pothole or abrupt stop, the magazine can become jammed. A very simple technique is nearly universal in its effectiveness to alleviate the situation.
Open the sliding door on the changer to reveal the magazine.
Slide the card under the magazine. You will feel the extraction tool engage a switch. Use a thin plastic ruler if the switch is too far back to reach with the credit card.
Press the "Eject" button under the magazine, while continuing to hold the card under the magazine. The magazine and all CDs should eject without harm to the media.