Powder puffs, foam eye-shadow applicators, and brushes all begin to collect makeup residue, oil, dirt, and bacteria that can cause pimples. By keeping them clean, you're much less likely to experience problems with blemishes.
How often you should give them a good cleaning depends on the frequency on which you use your brushes and the quality of your tools. Usually, two to three times per month is sufficient. Don't wait until you begin breaking-out to look for the culprit.4 Steps to Easy Makeup Brush Cleaning
Fancy solutions for cleansing are not necessary. You can use shampoo, dish soap, or facial soap.
It's wise to invest in high-quality makeup tools and brushes. They'll last longer and be able to hold up to frequent cleanings. However, cheap brushes still work, they just won't last as long, nor will they give you the smoothest complexion.