1. Cayenne pepper, rodent repellent, moth balls and ammonia
2. Bait
3. Traps, trash can lids, loud fog horn and motion activated misters
4. Rags and socks
5. Floodlights
Step #1:
Remember food and water will only lure squirrels into your car and thus to your car covers. Having known that these things can attract their attention, you must be vigilant about leftover food and trash which sometimes find their way close to your car. As much as possible, do not park in places where your car will be a few meters close to a pile of garbage, or even to a vegetable garden. Squirrels might be present in these high-risk areas and transfer to your car if they are close enough. If fruit-bearing trees are planted along your driveway, make sure that you routinely remove ripe fruits from the tree in order to discourage squirrels from climbing up. In many cases, squirrels that end up chewing the covers of your car come from these trees. Although it is not good to cut down these trees for the sole purpose of sparing your car covers from the squirrels, it is wise if the fruit-bearing trees are not planted along the driveway in the first place. Moreover, in order to completely remove all possible squirrel food sources, you must place all your trash bins in an area that is distant to your driveway. Bird feeders and pet food should also be kept far from the driveway.
Step #2:
Do you know that nocturnal squirrels hate too much light? Although most of these rodents are diurnal (forage by day), there are some species that also lurk at night. These are the same squirrels that chew on your car covers when you are sleeping or sitting on your sofa watching a football game. However, if you install a floodlight that has a minimum power rating of 100 Watts, you will definitely discourage these critters from ever coming near to your car. If you don't find floodlights energy-efficient, you can also try motion detectors that would only switch the light one when it senses movement around your car which is usually caused by squirrels. An instant flash of light is enough to scare away the squirrels and keep them that way for the entire night.
Step #3:
Now, although squirrels feed on almost anything, there are some types of food which they really detest. Item number 1 in the list given at the beginning of this article cites some of them. Seeds or nuts coated with cayenne pepper with a heating value of 90,000 BTU can serve as "landmines" which you can put around your car. Squirrels will feed on these seeds and nuts and get the full blast of the bombs in their mouth! A single cayenne pepper coated seed is already enough to burn squirrels tongue and scare it from going any further into your car. You can also try sprinkling cayenne pepper powder over your car cover. When the squirrels climb up or jumps down into your car, the powder will stick on their paws and once they start licking their bodies (including their paws), they will get a taste of the pepper and experience the same thing that the squirrels who have eaten coated seeds have felt.
Step #4:
You can also buy non-toxic squirrel repellents which you can buy from a pest control store or so an ordinary hardware. These repellents work just like cayenne pepper and some other natural squirrel repellents. The only difference is that these products are pre-processed and are ready to use; they are also stored in fancy containers which aides in easy dispersion of the product. You spray your car cover with these repellents and expect that the squirrels will no longer want to come any more closer to your car (perhaps because of the smell or the sensations that they get whenever they touch your car cover). Some of these non-toxic repellents are based on the smell of fox and coyote urine. These two animals are known to be great squirrel predators and in the wild setting, squirrels are naturally inclined to avoid areas already marked by a fox or a coyote's urine smell.
Step #5:
Squirrels do no like getting wet so if you install a motion activated water sprinkler close to your car, you will definitely frighten any of these critters that might attempt to come close.
Step #6:
You can also use mothballs to scare away squirrels. Make use of the fact that squirrels hate the smell of mothballs. Simply fill some socks with moth balls and place these socks around your car. You can also use pieces of rags, just soak the rags in ammonia and place the rags around the car. Mothballs and Ammonia basically have the same effects to squirrels.
Step #7:
You can also try "training" the squirrels to not go near your car. But in order to achieve this, you need to spend a little more time waiting for squirrels to indeed come near your car. Now, every time that they do so, all that you need to do is to bang two trashcan lids together (or any material that can produce the same sounds). If you are persistent and consistent, the squirrels will eventually get the idea that if they come near your car, they will hear annoying sounds.
Step #8:
Lastly, you can use traps to catch the offending squirrels. If you do not find this task easy, you can hire a professional squirrel control specialist to do the job. But if you are more inclined to try doing it on your own, all that you need to do is to set up the trap near your car and use baits to lure the squirrels into the trap. You just need to be patient though and wait up for the squirrels to come.