Eventually (especially for those of us that live in the north), you will be putting your RV into storage. We all want a nice heated garage, but often RVs find themselves in a barn or even outside. One huge issue is to keep mice away from your RV, as they can do significant damage by chewing on your RV and building nests.
There are two primary methods of rodent control; eradication (poisoning and traps) and deterrant. Notwithstanding any envrionmental or naturalist issues, deterrant is far more desireable than poison as it is better to keep mice out in the first place than having to deal with dead mice inside of your RV.
For that reason, we will be using the deterrant method; by using compounds that mice and other rodents do hate to be around, as well as sealing up the access points into the RV.
Our primary solution is a product called Mouse Away by Dreaming Earth Botanicals. It is a concentrate of both Spearmint and Peppermint oils, and it is very pungent. Mice hate the smell of it and simply stay away.
It's expensive though - about $15 for a 2 oz bottle. However, a little goes a long way, and we "apply" it by soaking a cotton ball in the oil and placing it in the bottom of a drinking glass. Three or four of these cups placed within the RV are all that are needed.
One caution though - do not use plastic cups. We found that the oil will melt the plastic commonly found in disposable cups.
If you use the mouse oil, it will soon stink the inside of your RV up. However, we used it last winter and found that letting the RV air out for a couple of days in the springtime during re-commissioning will dissipate the odor. We did not have any lingering Peppermint/Spearmint odor smells in our RV last season.
The Mouse Away product is also available as a "solid" consisting of little bags impregnated with the oil. However, I have always used the liquid and cotton ball approach.
Dryer sheets, such as Bounce also seem to work, although perhaps not as well as the oil. We typically use the oil in the interior of the RV, and the dryer sheets in the external areas - storage compartments, etc.
We have also tried different products, including "Shake Away" Rodent Repellant Granules, which we did not particularly like (they smelled awful). The way you are supposed to use this product is around the ground near the RV. However, in the winter time - when snow gets on the ground, as well as when it rains, the granules seem to dissolve in the run-off, which means you really need to re-apply each time it rains. For this reason, we have not had much success with this product.
While I have not tried it yet (as Mouse-Away works fine for me), several of my readers are using a product called Earthkind Botanical Rodent Repellent. So that is another option.
One thing I find interesting is EarthKind has several different repellents, including one for spiders. When I owned boats, it seemed like spiders like to live in fiberglass, and especially climb into the overhead rigging.
The second method we use is preventative. We simply seal up the RV as well as we can. Typically when the RV comes from the factory, there are all sorts of small crevices and holes that the mice can get in. I crawled around the bottom of the RV with a can of urethane foam sealant and applied it to any of the spots the factory missed. One caution though. Make sure you don't inadvertantly seal up any important drains, such as the low-point water line valves or refrigerator condensate drain.
Also, we run the electrical cable through a funnel into the RV. Normally, there is a 6" hole in the bottom of the RV to facilitate the routing of the electrical cable.
While the compartment itself does not let mice into the interior, they could still traverse up the cable and build a nest, or chew on the electrical wiring. Using a funnel is an effective method of keeping mice from running up the cable.
Do these methods work? All I can say is we tend to get mice in our garage from time-to-time, and our RV is parked outside of the garage. After one season of use, we have not had any issues with mice in the RV. Whether or not we were lucky or this is an effective treatment is hard to say, but in an area known to harbor a mouse or two, none of them got into the RV.
What doesn't work. I don't know about you, but I have never had any success with those electronic mice repellers. I think they are just ineffective.