A three-year-old and I had lots of fun with this. We hid the bones of one skeleton in fake snow, then found them using tweezers and tongs. We cleaned them off with spray bottles and a toothbrush, then built the skeleton. Three fantastic play sessions, and we've only used one skeleton so far!
A child finds this amazing because a flat piece of wood is transformed into a dinosaur skeleton very quickly and becomes something to keep and to admire and to show to relatives.