Get a cat.

I have mice living in my garage. There's no food in there. Well, I take that back. I had some Corn Gluten Meal in the garage for a while. Guess where some ended up? In my car's engine compartment. I think they were stashing it there. So, now I keep nothing at resembles mouse food in my garage, but they still come in and nest just inside the door.

Short version is, I caught ONE in a trap. I guess the others are too smart. I have dogs so I'm not using poison. I think cats are the only way to
go. :(

Here is some pretty good information.

http://www.health.state.ny.us/nysdoh/pest/mouse.htm

You need a couple of these.

Here is a link that might be useful: Wind-up mousetrap

If you are not going to be spending alot of time in the barn and are able to air it out when you need to be in there, moth balls work wonderful for all small critters including insects. But you need to be careful if it is sealed up the mothballs can make you sick. I use them at work in a building that was infested with mice and insects. I make sure to open oppossing doors or windows fifteen to twenty minutes before starting work and have experienced no ill side effects. And it covers the mice and insect odor. Good luck.

I'm wondering whether to try mothballs or peppermint/spearmint in my attic for mice/rats/critters?

My house appears to be well sealed from the attic but then again you never really know. An ounce of prevention is worth a pound of cure..........so if I mint out the attic will it get rid of the unwanted tenants???

can't us poison (gotta dog) don't want to use glue or traps cuz I'll have to climb up there and dispose of the carcasses, etc.