Cloves are the dried flower buds of tropical myrtles, used as spice — especially in deserts such as apple pies!
They are non-poisonous, sweet-smelling, readily available and inexpensive. What is interesting about them is that clothes moths find them totally unacceptable. Silver fish are deterred by them too.
I love the smell of cloves in my linen and clothes cupboards, and much prefer to use a natural product to a chemical deterrent.