I have a confession. When I first saw the Brush Egg in Sephora about a year ago, I hadn’t clue what it was. I came across it by the checkout outs (Sephora and their mini products by the checkouts. Always they nearly always get me!) and all in came in was a cellophane wrapper with a bar code. No description. Nada, but something said you’ll use it, so get it. 
Thinking it was a manual exfoliator I put in the queue with the other manual facial exfoliator/make cleansing better items to try. It wasn’t until watching a Real Techniques cleansing palette video a few weeks later, I thought about it and thought that’ll work instead. It was then I noticed the Brush Egg logo, did some research and found it is a make up brush cleansing tool. I can be really observant at times. In my defence there was nothing on the packaging explaining the product. Which is probably why both Sephora España and Sephora USA no longer stock it.
Anyways, does it work? Yes! It fits easily on my index and middle finger without moving. With clean hands, I put a little Dr Bronner’s Castile un-perfumed soap on the ‘egg’, wet the brush under running water (turn the tap off obviously when not in use), then run, twist and swirl the brush over the grooves, before rinsing the brush under warm to hot running water, squeezing the bristles between my index finger and thumb to remove any access water. Any product still left on the brush, I repeat the process. Next on some kitchen paper laid out (double sheet) I gently squeeze out any further water, leave until I’ve cleaned all my brushes before placing them brush end down, so as not to loosen the glue in some Real Techniques carry cases (that came when I purchased a few Real Technique brush sets. Cruelty free and I love them!) in to dry overnight. As I’m trying to reduce my waste, the paper towel is used during the week to wipe off access make up from brushes, fingers or help with mistakes, then recycled. I could place them on a towel, but for some reason I prefer paper towels (from recycled paper of course!).
The large grooves are great for larger brushes and lathering up, while the smaller spot like grooves really get in-between the bristles of smaller brushes removing residue product, dirt and oils . It’s easy to clean, rinse and leave to air dry. 
I’ve tried make up cleaner sprays, but find they’re more like hand sanitiser for brushes, a quick fix and smell weird. I prefer deep cleaning my brushes with the Brush Egg. When product starts to not apply like usual I know it’s time to clean them, however I try to stick to once a week either on a Sunday or Saturday to avoid any nasty bacteria building up. I also clean my Beauty Blender and cushion compact puff at the same time, again using Dr Bronner’s Castile liquid soap, thought it’d be great if neither to them absorbed so much product. The amount of concealer and BB cream that comes out cleaning them I swear is more than what I apply on my face!
How do you clean your make up brushes?