I've never been a fan of lens cleaning fluids. They leave smears. Yes I know you're supposed to use as little as possible. They still smear unless you wipe the lens aggressively after. Which I won't.Microfibre cloths - also a disappointment. When they appeared they promised to act like magic. Decades later, they're still failing to deliver. Why do we still believe in them?A blower is good.Next step a clean, clean, clean brush. Did I mention it needs to be clean?Other things I like are Visible Dust products and Calliope Opti Clean (great stuff that you apply to a lens then peel off, but has long since been discontinued. This is similar .)But these are possibly overkill for a dashcam lens. The Lenspens are something I've always had around and used occasionally and I think they'd be good for dashcams. My only concern would be if the lenses have coatings that might be less robust than on 'real' lenses, so gentle and sparing use would probably be sensible.