I’m not sure where you’re getting your information but the extract of castor beans are used to repel rodents that burrow in the soil. We sell it as a product called Mole-Max. It comes in a granular form as well as a liquid spray. It repels a wide range of burrowing rodents including chipmunks. You’ll notice a slight odor but it isn’t that noticeable. Here’s a link to the product description: https://www.bonide.com/trusted-brands/molemax/