Follow the safety instructions for work with chemical substances during work with the laboratory glass. Never use mouth for pipetting the chemical substances that are poisonous, caustic, irritating or dangerous to health. Such substances should be pipetted by pipettors that are available on the market.
Residues of precipitates from the surfaces of the laboratory glass can be removed by a suitable acid or by diluted solution of sodium hydroxide or sodium carbonate. We prefer acids because their erosion of the glass is much lower. Organic solvents like tetrachlor, trichlorethylene or acetone can remove bigger amounts of oil. Smaller residues of organic compounds can be removed by chromosulfuric acid. Careful rinse by tap water should be carried out after the removal of all impurities from the laboratory glass. Final rinse of the glass should be done by distilled water. It is also possible to rinse the glass by denaturated ethanol in order to improve drying.
Because we cannot exclude certain contamination of the laboratory glass during the transport, it is recommended to clean each piece of the laboratory glass before the first usage.