Hi, can someone please advise a non-arty primary school teacher. We have found a box of plain glazed ceramic tiles and a box of new acrylic paints in our art cupboard and would like the children to decorate the tiles to brighten a pebbledashed wall at the entrance to the school. Would this work? I assume I would need to seal the tiles with a spray on clear varnish. Any advice graefully received as we're trying to use resources currently in school to save the finances!