Closed Containers

Use a sturdy bottle with a screwtop lid. A screwtop lid does not leak and minimizes evaporation. Bottles with rubber stoppers, milk jugs with plastic snap lids, and parafilm covered test tubes are not acceptable - their contents can still spill or evaporate.

Close your containers tightly, except when you are adding or removing material. Make it a good habit. You don't want to breathe the chemical, even at low concentrations, on a day to day basis.

Got funnels? Funnels with tightly closing lids are available for a wide variety of containers. Use these instead of open funnels for frequently used bottles, and remember to close the funnel when you aren't using it.