Centralize the purchasing of chemicals through one person in the lab.
Take inventory of your chemicals regularly. Note the dates on the chemicals and dispose of any aging chemicals in a timely manner.
Use all of your older chemicals before purchasing or opening new chemicals.
Do experiments on as small a scale as is feasible, and periodically review procedures to see if the scale could be reduced.
Prevent students from over-dispensing chemicals.
Pre-weigh/pre-dispense chemicals that are needed for experimentation.
Store stock chemicals in small nozzled bottles
Prepare stock solutions prior to each experiment or on a regular periodic basis (for example, on every Monday) rather than keeping them constantly on the shelf.
Accurately label all waste bottles.
Detoxify or neutralize waste products if possible.
Substitute instrumental methods for wet chemistry whenever possible.
Purchase compressed gas cylinders or lecture bottles only from manufacturers who will accept the empty cylinders back.
Avoid mixing wastes.
Keep non-hazardous chemical waste separate from hazardous waste.
Avoid experiments that produce waste that is both radioactive and chemically hazardous.
Keep chemical waste separate from normal trash.