Neem Oil is used historically to repel fleas as well as mosquitoes and other insects. The other oils help to keep their skin moisturized. Peppermint and Spearmint is used to stop the "dog" smell, though historically both peppermint and spearmint can help heal dry irritated skin. Coconut, Castor, Olive, Neem Oils Cocoa Butter. Essential Oils of Peppermint and Spearmint.