The Brush Egg is used for deep cleaning makeup and other small brushes. It's compact, quick, easy, affordable and effective. It reduces the need for repeated use of brush cleaning solutions which can dry out bristles. With Brush Egg you can use whichever soap, shampoo or natural cleaning solution you choose. The smaller knobs on the top are used for foaming & lathering, the grooves on bottom are used to agitate the bristles to release the product, dirt, and oils. It also re-aligns the bristles without stripping them.