Permethrin is to be applied to clothing and material. It works by bonding to the fibers. When a tick or other insect comes into contact with the Permethrin, it absorbs a dose that will either repel or kill the insect. You apply Permethrin using an aerosol or trigger spray until the fabric is damp and then allow it to dry. Permethrin is easy to use and the resulting layer of protection is very important to your safety from insect-borne diseases.