You can do a quick clean with a lint roller, or go super deep with a soapy bath and toothbrush. There are lots of ways to clean screens depending on severity of the dirtiness, but just to stay on the safe side, it's important to deep clean all your window screens and door screens at least once a year- and there are some relatively easy methods to go about this unpleasant business. Not only do dirty screens obstruct your view, they can also affect the air quality that's filtered throughout your house. It's a chore most of us put off until it can no longer be avoided-meaning you can't see out your windows.
We've never met a single soul who gets excited about the prospect of cleaning screens.