How do I fix a car cd player that won't read cd?

My car stereo won't read the cd. I can hear it spinning and then it ejects it and displays E20. I have a 1997 Buick LeSabre. I have tried using one of those cd player cleaners that has the little brush on it but it ejects that also. I have also tried using canned air on it.

Mary
February 2010