In Germany, there are larger pests than mice called 'marder' I don't know how they spell it but its pronounced 'ma' as in Marmite and 'der' as in murder. Anyway these things climb into cars in garages and eat the wiring looms and rubber hoses. Well, being German, they have come up with an electrical device which gives these little monsters more than a bit of a shock, I think it is usually fatal. Please see :
ADAC Tipps - Marderabwehr
Marderabwehr - Was hilft gegen Marder?
Marderschutz - jetzt günstig bestellen! | A.T.U Auto-Teile-Unger
Maybe similar technology would protect against mice, rats, squirrels, small boys, etc.