My makeup brushes have been LONG overdo for a cleaning. Finally yesterday, after researching for ages and trying to find the motivation to take the time to clean my brushes (& let them dry), I cleaned ALL of my makeup brushes. I have quite a few Sigma Brushes and I know a lot of people use the sigma brush Dry'n Shape to help the brushes keep their shape but I didn't want to invest in one just yet so I made my own brush shapers.
After researching the best at-home makeup brush cleaners, I got Dr. Bronners Magic Soap (which apparently has like a ton of uses, but it is available in smaller sizes if you were only going to use it for cleaning makeup brushes). Some people dilute the soap, but you don't have to. We didn't dilute it at all, you just pour a little bit of soap into your hands and swirl the brush around and rinse it.
I bought thick elastic (I chose pink) and hot glued it together. I measured it around each brush to make sure it was the right size to actually hold the brush in the right shape and it worked like a charm! It was seriously so simple.