You can’t get much better for cleaning your plastic barrels than this.
If you want to remove all the plastic in your plastic barrels you will need to soak the barrels in water.
Put them in a bowl with plenty of lukewarm water.
Add some fresh or dried herbs and a bit of sandpaper to the water.
Pour the water into a plastic barrel.
You may have to remove the plastic cover to make sure it doesn’t clog up the drain, so you will probably need to use a pipe or tube to help you get the barrel clean.
Once the barrel is clean, you can put it back in the water and it will be ready to be used again.
You can also use a small brush to clean the barrel, but you might need to leave it on a shelf for a few hours to dry before you can use it.
Plastic barrels are typically sold in a glass tube or plastic bag.
They can also be bought in tubes or bags that have a metal cover, like this one from Aussie Furniture.