Here is a quick DIY for a Brush Cleaner Spray and you only need 5 items that you probably already have lying around at home!
*1 Cup water (dilute)
*1/4 Cup Alochol (disinfect)
*1.5 Teaspoon Dishwashing Soap (cleanse)
*Few drops of Olive Oil (condition)
*Empty Spray Bottle
Mix all the ingredients together and pour it into the bottle. I poured the rest into my Mac's empty brush cleaner bottle.
I tested it out on my Sigma F80 Brush that was extremely dirty (it needs a deep cleaning asap) but it did a pretty good job!
Here is the video: