Answer: Moth balls won't stop spiders but it will repel moths. About the only way to keep bugs and spiders out is to caulk all the tiny openings around windows and doors. If you're not opposed to chemical sprays, you can use one of the home pest control products on the market. They are safe to use indoors and out and should leave a barrier to repel insects for several months. Look in the pest control department of your local Home Depot for home pest control sprays.
Best wishes with your project!
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