buy the brightest skinniest maglight flashlight you can find, go in a dark room and hold the flashlight up to the fat end of the egg and then move it around to look through the egg at different angles. I always do this with a batch of hot wax (melted candle) on hand. Why... because when I first started I tended to drop and crack them, if it doesn't crack through the membrane you can dip in hot wax (quick dip) and it seals the crack.