If you want to really take care of your painting brushes, it's recommended that you clean them after each use preferably with soap. There are several brands of brush soap around. Anyway, I chose to buy the Da Vinci one since they are the brush maker and should know a thing or two about cleaning brushes.
When I read the reviews online, I realised that this is mainly used for cleaning cosmetic brushes. It's available in several sizes, such as the 100g soap bar, 40g, 85g and 231g circular block in a tin case. Mine's the 85g one and that's quite big so for those who don't paint regularly, I suggest going with just the 40g. But the nice thing about the 85g is it comes with a handy tin case for storing the soap which I always dry after using.
This is an all natural vegetable oil brush soap and includes conditioner so that the bristles won't over-dry and break. It's chemical free.
These are the instructions for washing the brush. Nothing too special.
I'm the kind of guy who doesn't do any extra cleaning and opt for just shaking the brush in water as my only form of cleaning, and so far my brushes are still surviving.
Above's the Da Vinci Maestro Voyage that I've been using since January 2014. Quite disgusting, I know. LOL.
This was how it looked when it was still relatively new. Gosh, I can't imagine how it has gone from this to the dirty state. Anyway, the brush still works great. Tip is sharp, bristles are still firm.
This is how it looks after I washed my dirty brush. Not much difference. The months of use have probably deposited the pigments onto the bristle that's making it difficult to clean off now. My poor brush...
I'm really careless with maintaining this brush. Even my other workhorse Da Vinci Maestro Travel Pocket Brush looks much cleaner after years of use. What I'm trying to say is, even without the brush soap, if you clean it with water regularly after each use, you can still get a clean healthy brush.
I read that people use this brush soap for cleaning cosmetic brushes for hygiene purposes. That's figures.
Overall, it's a good brush soap. It can help keep your bristles clean, but it cannot save paint brushes that haven't been maintained for a long time. Or to save money, just clean your painting brushes consistently after each use.