The main reason brushes are riskier than a blower is because they can pick up substances if you aren’t careful. Don’t touch the brush with your fingers to prevent oils from transferring over and make sure the brush stays capped or bagged to stay clean. Oils can be difficult to remove from lenses but they are even more difficult to remove from a brush you contaminate. Pre-moistened lens cleaning wipes are the next step up in terms of lens cleaning potency. Alcohol in the wipes help break down and clean off smudges.
The original lens brush has been popularized by the brand LensPen (2nd from the right in the photo above). It features a brush that slides out for use, and slides back in to stay clean. The other end is is a carbon-soaked polishing tip, designed to clean oil from fingertips and various sources without damaging the lens. Many competitors now produce the same product as well. We’ve accepted that our lenses and gear get dirty and will have to be cleaned. Ideally, we do what we can to prolong the time between cleanings with proper lens care. This includes doing things like using a lens filter, properly storing, and properly switching out your lenses, as well as generally avoiding touching the optics with your hands no matter how clean you think your hands are.
Microfiber lens cleaning cloths are an effective way to clean smudges. These cloths will cost you on average $2-4 dollars each but some cost as much as $10, depending on the brand. Microfiber cloths are pricier than lens tissues and are meant to be used for a long time before getting discarded or washed.