I spray mine with Permethrin for clothing/gear. Be sure to wipe off the lens. This is the one I use:
There was a similar post a couple months ago.
Best Products Sub $100 that you can get on amazon?!
Here was my submission, hopefully the links haven't changed.
While some factory pre-treated Permethrin clothing claims to persist through as many as 70 washings, you can get maybe six laundry cycles out of the spray (less on synthetic fabrics) before the insect-killing effect is lost entirely.