Some people have actually gone so far as to have an outside wall taken out, a bat house installed (prevents ingress into the house at large) and then sealed up save the small bat entrance. They enter, hang, sleep, exit. There is a tray that can be slid out, washed, and re-inserted. This is not for the faint of heart, as the potential for exposure to rabies and other toxic goo is high, but some do it nonetheless.