Flying Squirrels

[Anonymous Poster]

We have a family cabin in northwest Pa.. For years there have been flying squirrels in the attic that are a major nusiance. I've tried ammonia,mothballs,trapping them-no luck they keep coming back. I've tried sealing all the holes but there is a crawl space underneath - can't get to all the potential holes. We turn the power off when we leave so the electronic units won't help. Any suggestions?