Hi there, I have a Clarion radio/CD player that

There are usually two options 

1...See if you can tease the jammed CD out through the slot using another (old) CD

If not

2...The player will have to removed from the dashboard and opened up to remove the jammed CD.

Make sure you have the Security Code before removing the player.

.
 
If you do not have the code  then POST ANOTHER QUESTION

quoting the radio MAKE+MODEL plus ALL the LETTERS+NUMBERS on ANY LABELS ,BARCODES or STAMPED IN THE METAL CASING
 

note: Unfortunately not all radios can be decoded using the Serial Number