Holding a pipet at different angles will cause different drop sizes so be consistent. Label all your test tubes, especially when placing them in the centrifuge. Keep detailed notes of all observations noting both color and clarity. Always place a second test tube with an equal volume of water across from a test tube to balance out the centrifuge. Centrifuge for at least one minute, as it slows down, carefully use a paper towel to stop it.
All reagents go in the waste jar after use.
Leftovers are never put back in the original container. All waste containing silver, lead or nickel must be poured into the appropriate waste jars. Waste that contains only calcium, copper or iron may be rinsed down the drain. It might be convenient to appropriately label waste beakers for your bench, then to pour the waste into the waste jars at the end of the lab period. First you must test these ions individually to become acquainted with their reactivities.