If you need to clean makeup brushes or paint brushes, this tutorial is for you. This cool and easy way works even if the brushes are dry and crusty. All you need is a makeup sponge, a cordless drill brush cleaning solution or dishwashing liquid and a container.
Insert the bristles of the brush into the cleaning solution and start up the drill. Let the brush spin for around 10 seconds, then slightly raise it above water level without taking it out of the container. This will help flush particles from the brush's inner fibers.
Heat the vinegar to just below boiling, or just below 100 degrees Celsius (212 degrees Fahrenheit). If you don't have a thermometer, heat the vinegar until steam floods out, but it hasn't quite started boiling.
Luckily, I had some dried up brushes from a mural I painted last month. The brush on the right is before the vinegar soak and drill cleaning. The one on the left is the after. The soaked brush is soft and flexible again. The unsoaked brush is hard as a rock.
Protip: You may need to go through the soaking process a couple times if your brush is really encrusted.