I agree that snap traps are great as I have used them in my garage as well. The only problem I had with them was that once I had very small (young) mice that could steal the peanut butter without snapping the trap. That's why I used the sticky trap and it caught them all in a short time. The trick is to place it where they run, along the walls. You can find their runs by how much mouse poop there is in the area. I have never had to bait a sticky trap but that may be what is needed to lure them in in some cases.
Sticky traps are available at hardware stores everywhere. They are small plastic trays (3" X 4") filled with a very fast acting epoxy resin. Usually the mouse dies from suffication in the stuff. I have caught 2 mice in the same trap. Put out several to cover all travel routes. Sometimes you find them alive but that happens with any kind of trap including snap traps. Call me heartless but I just toss the trap and rodent into the trash. It is either them or me, LOL.