Over the years I've seen all sorts of items pushed into slot loading Apple drives, toy plastic coins, euro's, credit cards, even a card of rennies. Children often have fun seeing what they can push in. More recently lots of SD cards, as the two slots are adjacent. Very very rarely will shaking it on its side be effective. Only removing the glass, then the LCD, then the optical drive be effective. Once the optical drive is out, shaking it with the slot downwards may be effective, it may poke through the hairy slot. Usually the small screws around the side and some aluminium foil tape needs to be removed before lifting up the metal plate and extracting the SD card. If dismantling the iMac yourself 4 cables from the LCD need disconnecting. They are shorter on the 21.5" iMac, and easier to remove on the 27". Pull the LCD too far back while dismantling and and you rip of a connector on the logic board, that will write it off. Try to keep fingerprints and dust of the glass and LCD, they aren't easy to remove. And make sure it's unplugged from the mains before you work on it, the power supply PCB isn't covered and could give you a nasty shock.