Makeup brushes are an investment and if you take care of them you can use the same ones for years. Part of doing that is cleaning them and there's 2 ways to do that - spot cleaning and deep cleaning.
To spot clean:
|MAC Brush Cleanser|
Spot cleaning is a quick way to get color off your brushes (usually eye brushes) during the week when you don't have the time to deep clean them. I fold a paper towel into 4ths and put a little MAC Brush Cleanser on it. That way you can keep unfolding the paper towel to clean another brush and a little of the cleanser goes a very long way. Swirl the brush around on the paper towel to remove any makeup on it. This method is very fast and the MAC Brush Cleanser dries almost immediately.
To deep clean:
|Johnson's Baby Shampoo|
I deep clean my brushes about once a month and do it at night so they have overnight to dry out. It's very simple, just run lukewarm water over the brush, then use baby shampoo to clean the bristles. Once the water is running clear over the brush you've gotten it clean. Lay your brushes flat to dry on a towel and be sure to wring out any water in the bristles and reshape the brush.
Doing both these things will ensure you can use your brushes for years, which is great since some of them can be pricey. It's also good for your skin. Dirty brushes can accumulate bacteria, and since you're touching your face with them, that can cause breakouts. So keep them clean! :)