I had a the same issue this weekend. The disc stuck in my iMac was just a CD.
So, I had tried everything and was resolved to paying for a service of the iMac until I read on this forum about one last trick to try.
When booting the mac I held down the right mouse button. (in my case the right trackpad click as I do not use a mouse).
Once the OS was up the CD showed as usual as a CD on the desktop, I hit eject and out it popped.
I had tried everything for days to get it out, my imac was at one stage stuck in a repeating cycle of attempting to eject the disc, some how the mechanism just failed to 'grab' the disc and spit it out.
It may help, but I suspect you have an extra issue because you state there was a plastic protector that went it as well.
i have resolved never, never use that optical drive again, this is not the first time I have faced this issue. Never again. Serious design flaw in my opinion.