Balance the tube precariously on the edge of a table or counter with the treat hanging directly over the tall sided receptacle. The mouse will scurry to the treat (they like tunnels) and fall into the trap.
I learned this technique from the Kapulainen kids when spending childhood summers in Turku archipelago. They were using it to catch a forest mouse to keep as a pet. It didn’t work with rats, though, as they were strong enough to jump out of the bucket after capture.
I’d completely forgotten the episode until I ran into this story on Boing Boing tonight.