Best deterrent for me for many years was moth balls. EVERYTHING, including us, hates that smell and it took half the summer to get it out of the cars !! I tried the dryer sheets one year, but it was too convenient for the rodents to chew up and make warn nests out of. I tried a new product called Critter Crumbs several years ago and have used that exclusively ever since. No issues with mouse intrusion and the smell is strong peppermint, but reasonably pleasant and goes away quickly in the spring when the product is removed and the windows left open for a few hours. Search the name and you can order it online and have it shipped. A little spendy for some, but it takes very little and can protect several cars for the cost, AND it actually works. They make another similar product for enclosed spaces such as your shed too.