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How to Clean Plastic Herbicide Barrels

In an effort to reduce waste, many people recycle empty plastic herbicide barrels. Depending on their size, these barrels can be used as compost bins, rain water reservoirs or planters. But before these barrels are repurposed, they must be thoroughly cleaned. Residual herbicides on the surface of the plastic could contaminate your plant water source, kill your potted plants or contaminate your compost.

Empty any remaining herbicide onto barren soil that is far removed from any water sources, including the water table. Allow the herbicide to drip or pour out for at least 30 seconds.

Fill the barrel one-quarter full of water and shake it or seal it and roll it on the ground.

Rinse the inside and outside of the barrel with the spray from a hose for at least 30 seconds.

Fill the barrel with a 1 to 25 ratio solution of ammonia and water (5 oz of ammonia per gallon of water). Leave the solution to soak overnight.

Pour the solution out of the bucket.

Scrub all parts of the herbicide barrel with a brush dipped in a fresh batch of ammonia solution.

Rinse the barrel again by spraying it with a hose for at least 30 seconds. Then fill the barrel with water and pour it out twice.

Allow the barrel to air dry.

Ways To Clean 55-gallon Plastic Barrels

Garden uses for 55-gallon plastic barrels include rain barrels, compost barrels and container gardens, but the barrel must be cleaned to remove any trace of its former use. Do not clean or use a plastic barrel that held toxic or hazardous materials. If the lid is not removable and you don't want to cut off the top, fill it about one-fourth full of water and add 1 cup of bleach. Secure the small bung cap to the barrel top, tilt the barrel on its side and roll it back and forth so the solution sloshes on all sides. Rinse the barrel several times with clean water to remove any residual bleach. Castile soap mixed with vinegar also works to clean the inside of a 55-gallon plastic barrel. Food-grade plastic barrels often have lingering odors from whatever was previously stored inside the barrel. Baking soda is also a mild abrasive, so you can use it to scrub away any stuck-on debris or algae from the sides of the barrel.


If you merely plan to dispose of your herbicide barrel, simply repeat Steps 1 through 3 three times. There is no need to clean it with ammonia.

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