Silver from photographic fixers can be recovered. Chemical Neutralization Neutralize dilute acids and bases in the lab. Good Management Maintain an inventory of chemicals in the area and discard those no longer used. This will also prevent duplicate purchases. Label all materials.
Unknown materials are expensive to analyze.
Purchase the smallest possible amounts of chemicals. Use waste generation as a criteria in the selection of new equipment. The cost of disposing of excess can easily outweigh initial savings. Consult your colleagues, someone else may be able to use surplus. Train employees in waste management practices.