Dust is everywhere and everywhere is dust. It will get on and inside your lens. Lenses are manufactured in extremely clean factories, where manufacturers go to great lengths to try to eliminate dust from the environment. Even then, brand-new lenses may have dust between the lens elements.
Dust, however, is not the main enemy. A lens that sits on a shelf in your home for years and collects a thick layer of dust will, obviously, produce image-quality issues. But, a few specs of dust here and there on or inside the lens will have no effect on image quality. A few specs of dust on or inside the lens will have no effect on image quality. That statement was intentionally repeated.
Trying to keep your lenses dust free through continual cleaning may serve to shorten the life of your lens, as you run the risk of scratching the lens surfaces every time you clean the glass.
Remove as much dust and dirt as possible from the lens with a blower or soft bristled brush.
Apply a few drops of lens cleaning solution to a lens tissue or cleaning cloth.
Using a circular motion, gently remove oil, fingerprints, and grime from the lens surface, working from the center outward.
This is only solution making ides, not a complete solution.