Gunk - Play Dough
WARNING: Non-Edible green food coloring
Add food coloring to the water to desired color, stir into the cornstarch. When the cornstarch is dissolved, drop the whole batch onto a tray for the child to play with. This is almost a liquid, so makes a fun change from other doughs. Clean up is the easiest of all doughs, as when it dries it is simply swept up. Any that is left can be placed in a clean glass jar and let dry. It can then be reconstituted by simply adding water.