I recently saw this tip mentioned by Siobhan on her youtube channel 'LetzMakeup' (the video is here if you want to check it out). I thought it was so good that I'd share it!
Siobhan suggested using a micellar water containing alcohol as a brush cleanser. I had never considered this but it makes total sense. Micellar water is obviously designed to remove makeup from the skin. It wouldn't normally be enough on its own since it doesn't contain a disinfectant. However, the newer versions of the Garnier micellar water contain alcohol, which will kill any bacteria and nasties.
It is also far cheaper than most brush cleansers, especially when you can regularly get it on offer for around £3-4 for a huge 400ml bottle. I picked up the Pure Active version as it was on offer when I was in Superdrug (£3.29 here) but you could also use the combination skin version as it also contains alcohol (currently £3.33 via Boots here). I use this to spot clean brushes that I want to use again quickly as it dries within a couple of minutes. All you need to do is to put a few drops onto a cotton wool pad/ face cloth/ whatever else you want to use and gently rub the brush onto it. As you can see from the above photos, you very quickly have a clean brush! I do also deep clean them with Dr Bronner's soap every 1-2 weeks, but the micellar water is ideal for spot cleaning.
What I will say is that I would not recommend using the alcohol heavy micellar waters on the skin as it can dry it out, irritate it and actually make oily skin oilier because your skin feels like it has to rgreplace the lost moisture and goes into oil producing overdrive. I much prefer the original, alcohol free version (currently on offer for £2.79 via Boots here) for use on the face, which is far less drying. The alcohol containing ones make the perfect budget friendly brush cleaner, though!
Thanks to Siobhan for the top tip!