I use dryer sheets - the more the better. Plus it keeps the camper smelling good. And we store ours in the country as well.
Mice pooped on all the dryer sheets we put in our new tt! We have found (so far) that Fresh Cab packets and the peppermint oil in cotton balls seem to work...
We just opened up our camper yesterday and found no evidence of mice or spiders. We live in the country as well, with our house pretty much surrounded by woods. This is our third year of using a combination of Fresh Cab along with peppermint oil all through out the camper. I will keep using this combo because it is definitely working for us.
Windjammer came out of hibernation yesterday (horse barn at local fair ground)
did a thorough search no sign of mice...used cotton balls placed in tin containers soaked in Essential oils of peppermint strategically place throughout the TT...plus the WJ has a very pleasant fragrance.
Not a bad way to start de-winterizing.
Happy Trails
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2017 Columbus 340RK
GMC Sierra 3500HD Z71 6.6L Duramax/Allison