I had a very difficult time removing the SD card I was trying to exteract from the CD slot - I was almost at the point of giving up and taking it in for a repair - I had tried the paper/cardboard method, reinforced with tape, and the cardboard started to rip, almost leaving ANOTHER piece of detritus in the slot - I then VERY carefully taped the section that was ripped and tried to remove the cardboard "L" shaped tool - it appeared to be totally stuck, and no amount of wrangling would free it. I then tried to insert to insert (additionally) the short side of a 4x6" index card about halfway in, and that allowed me to free the cardboard "L" tool. I'm guessing that it held down the "catch" that locks a CD in place, enabling me to free the stuck cardboard "L" tool.
Deciding that paper/cardboard was not going to do it, and after trying for over 30 minutes, and not wishing to risk another tear, I fashioned a similar tool out of a very thin sheet of plastic, from a plastic folder - I wanted something thin and flexible, but nothing that might rip, and leave more debris in the drive slot. I tried with this new plastic version for an additional 15 minutes or so. I was also shaking the unit ("shaken iMac syndrome"?), and mostly trying to shake it firmly down, with the slot positioned at the bottom. Still no luck, it seemed that the SD card had somehow become firmly lodged somehow within the drive. I tried some more shaking, some tapping with the heel of my hand, and fishing with the plastic "L" tool - and eventually - Mirabile Dictu! - about 1/16" of the corner of the SD card appeared. I VERY (VERY!!!) carefully pinched that corner and slid it right out. WHEW!!!
Needless to say - from here on out, I will be VERY cautious about not inadvertently inserting the SD card in the wrong slot. DOH!!!
Hope this helps someone else - be patient, keep trying - I might recommend to avoid the bent paper clip approach, so as to not cause any damage...