Concentrated pesticide residues leaking from unrinsed, discarded containers can cause significant environmental contamination. Up to 3 ounces of pesticide may be left inside a 5 gallon container after normal emptying. Depending on the cost of the product, the money saved in pesticide cost alone through proper container rinsing could be significant. Containers should be rinsed immediately after they are emptied because residue can dry and become difficult to remove.
Triple rinsing is the most common procedure for rinsing containers. It involves filling each container at least one-quarter full with water, replacing the lid, shaking the container, and then emptying the liquid from the container into the spray tank. This is done three times with each container. A new approach, pressure rinsing, allows containers to be rinsed while pesticides are emptied into the spray tank. Special nozzles attached to a garden hose are used to puncture plastic and metal containers (Fig. 3). When turned on, the nozzle produces a forceful spray inside the empty container. By holding the container over the opening of the spray tank or holding tank while rinsing, the rinse water can be captured as it drains from the container spout (Fig. 4). It takes a few minutes to properly triple rinse a container, but less than a minute to pressure rinse. The amount of rinsate generated is also reduced with the pressure-rinsing method.