Had a mouse/rat/squirrel/etc. problem for several years. Tried everything - traps, charcoal, filled EVERY hole I could find, softener sheets, etc. The ONLY thing that worked was picking up a couple free cats, feeding them everyday, and providing water/shelter for them. Eight years now and not a single problem. I will admit that we do miss the birds at the feeders in our yard, but that is a small sacrifice for the damage the rodents did to our trailer. The cats (I call them mousers) have never been in the house. They are 100% outside. And yes, the cats have been neutered at "Neuter Scooter" for $35 each.