I can’t help it.  Another idea using the last mouse funnel occurred to me.

What if you had a long tube with a series of bristles all pointing in the same direction just like the mouse funnel?  Put some peanut butter on the outside, install in a door, and walk away happy and content that you’re saving mouse lives.

Once the mouse started down that tube it wouldn’t be able to turn around or back up easily.  Given the option of unlimited freedom outdoors and chewing its way back through pokey bits, I can’t imagine it would choose plastic splinters.