When using glazes with elementary students always read the health label.
Cherry Reds usually have some kind of cadmium in them so I would avoid that
color. Have them use a non cadmium red paint to add that color on the
surface after it is fired. Clear glazes that contain a lead bisilicate are
suspect and I wouldn't use them with elementary school children even if the
label says, "safe for food". I would only use a leadless clear glaze.