Calcium chloride, potassium carbonate and sodium carbonate are weak acid or bases respectively and have to be handled with caution. Magnesium sulfate, sodium sulfate, molecular sieves and silicagel do not need special safety precautions. For all powdery substances, dust should be avoided during decanting to prevent uncontrolled release of the substance or exposure of the decanting person. Therefore, the last four drying agents should be used in schoolary and undergraduate education.