grade I highly recommend this way of coloring them. That way the glaze won't fill the holes. They break if you stack them horizontal! Also, do not use air dry clay, as they are too fragile. Stoneware is a must.
Maybe for Charlote's Web (?) Water color crayon resist artwork, an Original watercolour painting by Kirsten Bailey, but could be adapted for a children's art activity. Great for a fall wall hanging or spider picture for the fridge!