It's inevitable that when you apply eye shadow with brush, some of the powder will fall apart to your cheekbone. When the color is neutral, it's still easy to clean up. Trouble starts when you're applying black eye shadow powder and suddenly your cheekbone turns dark. So what you can do is:
1. Take some loose powder with your brush then put it under your eyes. Choose powder that has one color lighter than your skin to keep your undereye for having dull skin color.
2. After finishing your eye shadow application, use powder brush to brush away all the excess powder on your undereye.
You're done! Your eyes are all set.