I thought the same when I first started... Then I decided that they needed to go when they like DOUBLED population over night!!! YUCK!
I got joes juice and they never came back.
If you don't wanna use chemical, you can try the peppermint shrimps but I don't know whats in your FOWLR tank, so they may get eaten. Also, sometimes the shrimp are lazy and don't eat anything but fish food. Little brats...