Cobalt Sulphate(CoSO4) is a water soluble form of cobalt.  Water-soluble metal salts should be stored in containers separate from regular glaze mixtures and should be well labeled to avoid any accidental mixing of the chemicals.  A suitable respirator should be worn when measuring and working with water-soluble metal salts so that chemicals are not inhaled or ingested. Suitable hand protection should also be worn because skin can easily absorb these chemicals.