Q: How can I clean weed killer chemicals out of my sprayer?
A: Using the same garden sprayer to apply weed killer and also insecticide can be costly! It is difficult to remove all traces of some herbicides from a sprayer. It is by far the better idea to use one sprayer only for weed killers and to purchase another for spraying insecticides and fungicides.
If a sprayer needs to be cleaned, mix one fourth cup of household ammonia with one gallon of water in the sprayer. Shake the sprayer vigorously and pump it slightly to force some of the solution out of the nozzle.
Let the sprayer stand, filled, for six hours. Empty the sprayer and fill with clean water. Spray the water through the nozzle. Repeat once again with more fresh water.
The tank can be turned upside down to dry before using the sprayer for other pesticides.