I use mouse traps and moth balls both. If I notice my mice are dirty, I'll try the Irish Spring soap. LOL
I have a major mouse problem, and I'm not sure moth balls are the answer to anything. I also put one of those poison blocks in the engine compartment just to check if it has been chewed on. I have multiple traps around my machine and keep them checked at least weekly, and they must be freshly baited (peanut butter is good bait). I became very defensive after mice put my lawn tractor out of commission by chewing the wiring. They like some of the wire coatings that some manufactures use instead of rubber. They seem to like my John Deere wiring material.