I know that when I own a house I'm definitely putting up bat houses. I want bats! I hate mosquitos! I don't want any pests in my house (you know, except the damned cats!)...

Most of the suggestions involved cardboard boxes and opening windows and suchlike. The flashlight I found particularly useful. No one had anything failsafe -- I was hoping for a solution like "next time, have a cowbell handy. Stand on one foot outside the house, ring the cowbell, yell "Shazam!" and you'll be guaranteed to be bat-free."

Why aren't there solutions like that?! I would like a solution! I need to live in the Harry Potterverse, clearly.