The vial of yellow glaze was used during the Egg-streme Management. It was used to create different combinations of glaze colours with the other two primary glaze colours, red and blue. When attempting to leave the cave with this vial, it will be removed from your inventory. When mixing too many colours together, it gives you a Bowl of black mess, which is useless. This item was removed from the game at the end of the Easter 2010 event.