I just saw this facebook post claiming that vinegar and essential oils can repel ticks.
In a spray bottle, mix 2 cups of distilled white vinegar and 1 cup of water. To make a scented solution so you do not smell like bitter vinegar all day, add 20 drops of your favorite essential oil.
Eucalyptus oil is a calm, soothing scent that also works as a tick repellent, while peppermint and citrus oils give off a strong crisp scent that also repel ticks.
After mixing the solution, spray onto clothing, skin, and hair before going outdoors. Reapply every four hours to keep ticks at bay, and examine your skin and hair when back inside to make sure no ticks are on the body.
A quick search also led me to a post on MDJunction "Essential Oils to Kill Ticks":
Natural alternatives for pest relief are in great demand. Essential oils are a popular choice, and some can repel ticks even if they don't kill ticks. In 2004, Swedish researchers Gardulf, Wohlfart and Gustafson found that the mosquito repellent Citriodiol lessened tick attacks on people by 34 percent.
The essential oils most commonly promoted as tick repellents include clove, eucalyptus, lavender, lemon, geranium, palmarosa, pennyroyal, rose and sweet myrrh.
Do vinegar and essential oils actually repel ticks?