I do not understand the "too small to set off traps" bit. I use Victor rat traps out in the woodshed and catch mice with them all the time.
Not only peanut butter, but pinch a raisin on that trigger, kinda mash it into the cutouts, then spread peanut butter on that. Works really good it seems if the raisin gets dried out and hard as the little bastids have to work at it, no licking it off the trigger.
And I use a product called RatX and MouseX, kills mice and rats without harming other things..........supposedly.
And Shake Away or Fresh Cab repellent. Especially under vehicle hoods, seems to work pretty well in the woodshed too as I only catch a few mice every winter now.
Raisin on a Victor Trap as above.
Mash the raisin on the bait holder so it's opened up[smell].
They can't resist.
