When storing glass stopcocks and joints insert a thin strip of paper between joint surfaces to prevent sticking
Never store stopcocks for long periods with lubricant still on the ground surfaces
Glass stopcocks on Burettes and separating funnels shouldbe lubricated frequently to prevent sticking
  • If a ground joint sticks, separation can generally be achieved by carefully rocking the cone in the socket, or gentle tapping the socket flange on a wooden surface, or by heating the socket and not the cone in a localized flame. The use of penetrating oil will often prove useful in aiding separation
  • In using lubricants, it is advisable to apply a light coat of grease completely around the upper part of the joint. Use only a small amount and avoid greasing that part of the joint which contacts the inner part of the apparatus
  • Three types of lubricants are commonly used on standard taper joints
  • Hydrocarbon grease is the most widely used. It can be easily removed by most laboratory solvents, including acetone
  • Because hydrocarbon grease is so easily removable, silicon grease is often preferred for higher temperature or high vacuum applications. It can be removed readily with chloroform
  • For long-term reflux or extraction reactions, water soluble, organic and insoluble grease, such as glycerin, is suitable. Water will clean glycerin
There are other types of greases, which can be used specifically when certain reagents are used in the Burettes or separating funnels.
  • The use of water, oil or glycerol is recommended on both tubing and rubber bung when inserting glass tubing into a bung. Always wear heavy protective gloves or similar protection when carrying out this operation
  • Always fire polish rough ends of glass tubing before attempting to insert into flexible tubing. The lubricants recommended above may also prove useful
  • Never attempt to pull a thermometer out of a rubber bung, always cut the bung away
  • Use tongs or asbestos gloves to remove all glassware from heat. Hot glass can cause severe burns
  • Protective gloves, safety shoes, aprons, and goggles houldbe worn as safety against chemical accidents,spilling or splattering
    • Always flush the outside of Acid bottle with water before opening. Do not put the stopper on the counter top where someone else may come in contact with acid residue


    • Special care is needed when dealing with mercury. Even a small amount of mercury in the bottom of a drawer can poison the room atmosphere. Mercury toxicity is cumulative and the element’s ability to amalgamate with cumulative and te element’s ability to amalgamate with involving mercury, the area should be gone over carefully until there are no globules remaining. All mercury containers should be kept well-stoppered
    • Never drink from a beaker. A beaker left specifically for drinking is a menace to the laboratory. Do not taste chemicals for identification. Smell chemicals only when necessary and only by wafting a small amount of vapour towards the nose
    • Avoid pipeting by mouth, particularly when using concentrated acids, alkalis or potentially biohazardous materials. Use mechanical means such as a rubber bulb or a automatic dispenser
    • Never fill receptacle with material other than that called for by the label. Label all containers before filling. Throw away contents of unlabelled containers
    • To avoid breakage when clamping glassware, do not permit glass-to-metal contact,and do not use excessive force to tighten the clamps
    • Do not look down into a test tube being heated or containing chemicals, and do not point its open end at another person. A reaction might cause the contents to be ejected, resulting in injury.
    • Splattering from acids, caustic materials and strong oxidizing solutions on the skin or clothing should be washed off immediately with large quantities of water
    When working with chlorine, hydrogen sulphide, carbon monoxide, hydrogen cyanide and other verytoxic substances, always use a protective mask or perform these experiments under a fume hood in a well-ventilated area
    • In working with volatile materials, remember that heat causes expansion and confinement of expansion results in explosion. Remember also that danger exists even though external heat is not applied
    • Perchloric acid is especially dangerous because it explodes on contact with organic materials. Do not use perchloric acid around wooden benches or tables
    • Keep perchloric acid bottles on glass or ceramic trays having enough volume to hold all the acid in case the bottle breaks. When using perchloric acid, always wear protective clothing.

    • When using hot plates and other electrical equipments, ensure the wire and plugs are in good condition. Never handle electrical connection with damp hands.