I didn't see an answer to the question about using moth balls, but that sounds like it might work, to me!
Moles and Moth Balls
Certified GKH Gardening Expert
As long as the area you are using isn't for plants that you will consume. The plants will take this up, and it can be quite toxic. As long as you are not going to consume these plants, then it might be ok. But just make sure this is not contaminating anyone else's property, as these chemicals can be rather toxic.
Moth balls may repel small animals and some insects but they are highly toxic, especially those formulated with benzene. This means pets, other wildlife and children are at risk. Inhaling fumes is unhealthy and it takes quite a few moth balls to achieve repellent effects. You may like this website: http://icwdm.org/ControlMethods/Mothballs.aspx