This happened to me twice in the last two months! My Sony would not release a CD, so we felt it was time to buy another one. Found out from the Good Guys installer that the Sony had quite a few coins in it. Bought a new Kenwood CD, and guess what? My son put coins in it yesterday! He proudly told me about it, of course...(he's 2). Well, I called Good Guys and they said they'd send it out for two to three weeks to have the coins removed. Then they could repair any damage to the machine. Well, I did not want anything to do with that. I got out my accessories and found the removal tools, pulled out that stereo, disconnected it, and used a screwdriver to remove the top of it. I could see four coins in it. Two were loose in the centera area and two were sliding on the edges. I got my tweezers and played Operation for a few minutes. Three pennies and a dime later, I closed it up, hooked it back up, and it worked just fine! So then I got out the old Sony and did the same. Five coins in that one, and the one that caused it to not release the disc was a penny that wedged between the release gears. I was in the market for a new CD player for my husband's old truck, but didn't want to spend any money. Good Guys installers said they could put the Sony in it for 60 bucks, or I could try it myself. So I wrote on the Audio-Video forum and my friend Shindog has given me complete instructions for switching out the truck's old player. I will be doing that this weekend. I'll let you know if it works.
So what's the moral of my story? Well, either your player is shot or it's not. Open it up yourself and see if the coin is visible and take it out if you can. If it simply fell in, no damage done. And if it's somewhere you can't see, then close it up without doing anymore and decide whether you want to send it for service.
I bet it's just fine. Good luck!