It’s something many people do on a daily basis, but the brush you're using to apply your makeup could be riddled with germs.
Speaking to Stuff, Professor Richard Cannon, a microbiologist at the University of Otago said: “Bacteria like to grow in moist conditions and on organic substrates.”
"These days sponges tend to be made from some sort of plastic, but they'll retain moisture. So bacteria are more likely to survive on a sponge than in a brush."
Applying makeup with a dirty sponge or brush could mean you are transferring bacteria from one part of your face to another, leading to breakouts and congestion.
"You could spread bacteria over the face where it might have been localised, and they could have grown in between uses on the applicator," Cannon says.
It turns out, the safest way to apply makeup could be with your fingers, as long as you’ve washed them.
"Hands would be better, especially if you've washed them. Your hands are often touching your face anyway, so you're not introducing anything new."
How to clean your makeup brushes
Run your brush under warm water and apply an anti-bacterial soap or shampoo. Swirl the brush in a bowl of water to remove any excess makeup. Rinse under running water. Repeat this step until the water runs clear.