James B. You said, “Put the trap in a plastic bag and find a blunt object. Squish the head. The animal is dead instantly. Your squeamishness is no excuse for suffering.”
That advice may work for the first day on the job as a mafia hitman.
Frankly, I am glad all our advice does not use up the ink on this page. There are exterminators already using humane methods to get rid of mice quickly, and to ensure any possibility of disease is nipped right away. No one has to run around with plastic or hammers or funnels or nosh or buy cats or whatever or make motel reservations or whatever..
Call the professionals: Always go humane!