It is important to keep laboratory glassware clean. Glassware should be cleaned with laboratory designed detergents provided by the instructor. Clean as soon as possible to decrease the amount of buildup which makes cleaning more difficult. When using brushes, be careful to avoid damaging the surface of the glass product. 

After washing glassware, be sure to rinse thoroughly to prevent contamination. It is not advised to towel dry, instead allow glassware to air dry. Inspect the surface to ensure it is free from any defects or particulate matter. Any glassware with chips, cracks or scratches should be removed from service and disposed of properly.  

Glassware that is jammed together or frozen should be carefully released by someone wearing appropriate protective equipment such as cut-resistant gloves and goggles to prevent injuries. Two examples of frozen glassware are nested glassware that is stuck together and immovable stoppers. 

Even the most carefully executed experiment can give erroneous results if dirty glassware is bought to use. If the glassware that is used for measuring liquids is contaminated with grease and other materials, it prevents the glass from being uniformly wetted. This in turn will affect the volume of liquid delivered and the amount of residue adhering to the walls of the container. Likewise, presence of impurities in glass labware can distort the meniscus and can prevent one from getting the correct results out of the science lab experiment. 

Even the most carefully executed experiment can give erroneous results if dirty glassware is bought to use. If the glassware that is used for measuring liquids is contaminated with grease and other materials, it prevents the glass from being uniformly wetted. This in turn will affect the volume of liquid delivered and the amount of residue adhering to the walls of the container. Likewise, presence of impurities in glass labware can distort the meniscus and can prevent one from getting the correct results out of the science lab experiment.