Here is an easy way on How to clean makeup brushes with vinegar!! It is important that you clean your brushes on a regular basis, because it captures germs, and tons of product that begins to build up. I need to set a schedule on when I clean mine, because I forget to do it at least once per month. My foundation brush needs it like 1 time a week!
How to Clean Brushes:
In a cup add 2 parts warm water to 1 part vinegar. Then add a couple drops of dish soap (I use Dawn) and then swish around and then put brushes in to soak. Then once they have sat for about 5 minutes, go and swish them around, and rub softly on the bristles. I do one brush at a time, and you will be amazed at how much makeup will come out. Then I run warm water and finish cleaning each brush one by one. If it still looks to have more makeup stuck on it, I will add a drop of soap and wash it under the warm water until it looks clean and runs clear water when ran through.