Originally Posted by zetune

If it is just one chunk of porcelain (as opposed to small shrapnel) I have had success getting objects out of cylinders with a piece of wire (Basic automotive 16 guage primary wire) and a piece of duct tape or bubble gum balled at the end. you can prod around in the cylinder and as long as you don't get too much oil on the sticky part you may be in luck.
Don't lose the bubble gum in there too though. I did that the first time the learned to loop the wire and then ball up the gum (Chick pea sized ball) this keeps the gum on the wire... trident worked well HA HA.

If pieces are small you can turn the engine over with the starter with the plugs out and if your lucky the pieces might come flying out the spark plug hole. (This is very dangerous as the porcelain will do a lot of damage to the cylinder if it rubs.)

Good luck