Squirrels do hate certain strong smells, such as cider vinegar, spicy or hot odors, mothballs, animal urine and skunk-like smells. Squirrels have a strong sense of smell that can detect food from great distances.
Squirrels often hoard food and use their elevated sense of smell to later detect where they hid their food. Cider vinegar and spicy odors, like garlic and pepper, can be used to keep squirrels away as the smell repulses them. Animal urine and skunk-like smells also deter them, as these smells help squirrels detect a threat in the area. Animal urine, specifically that of a predator, can warn squirrels of a daunting threat.